I've been playing Sardinia-Piedmont a lot since release and I've come up with a strategy that let me form Italy somewhat reliably. As a disclaimer, I haven't tried this with any AI mods yet but I expect most of the tricks to still work.
General Situation
While Two Sicilies has more pops and more states, Sardinia-Piedmont still has a few aces up its sleeve.
- Resources-wise, Sardinia-Piedmont has all the goods needed to set up an industrial economy. Their starting resources are especially suited to heavy industries: iron, coal, tools, steel, motor, glass, and sulfur. Those goods are used to reduce construction costs either directly or by facilitating the production of said goods. Getting cheap iron especially can drastically reduce the construction cost which means they can build more. Furthermore, motors and glass are pretty much always in high demand early on making them a good contributor to the GDP. Having access to Cotton for fabric and Silk through the other Italian nation also makes setting up a cloth industry quite profitable.
- Sharing a border with France and Austria means that Sardinia-Piedmont can safely trade a high volume of goods. For obvious reasons, you don't want to get too cozy with Austria so it's better to trade with France. Doing so let Sardinia-Piedmont easily balance its market letting them specialize their economy without having to be in a customs union. The goal shouldn't be profitability but volume of trade. The more volume you trade with France, the more likely they are to accept a trade agreement which in turn makes it more likely to get a defensive pact or even better an alliance. In contrast, the Two Sicilies has to trade by sea which limits the volume of goods they can exchange to their convoy capacity and made them highly susceptible to raiding during a war.
- Having economically viable states can be somewhat of an advantage. Setting a decree for resource extraction in Sardinia, our mining state, and a manufacturing decree in Piedmont gives a +20% throughput to those key industries and makes economic planning easy.
- Geographically, their position is relatively safe with a friendly France west, a weak and generally pacifist Switzerland north, a protective Austria east (until you move against them), and a bunch of Italian minors south. Austria and France also tend to have a protective or cooperative attitude early on meaning that there isn't much of an immediate threat.
Starting moves
- Construction: Build two construction centers in Piedmont, 2 administrative centers in Piedmont to fix the taxation deficit, 2 iron mines followed by a coal mine in Sardinia.
- Tech: Get Atmospheric Engine -> Water-tube Boiler -> Mechanical Tools.
- Reform-wise, start by enacting Charity Hospital, and Religious Schools. After that, you want to start chipping away at the influence of the aristocrats by getting Dedicated Police Force, Appointed Bureaucrats, and Landed Voting.
- Authority: Add a consumption tax on Wine and Services. Bolster the Industrialist. Set a Resource Extraction decree in Sardinia and a Manufacturing Decree in Piedmont. The rest of the authority to spend is up to you depending on the circ*mstances.
- Diplomacy: Improve relations with: Lucca, Modena, Parma, Tuscany, and France.
- Declare an interest in Southern Germany.
Early Goals
- Archive Major Power status. My general target is to focus on the economy for the first decade and then shift my construction to military goods, barracks, and dockyards to get the necessary prestige. If that's not enough, building and subsidizing 2 art academies should provide 60 prestige to get major power status. Just delete those when your position is safe so that you wouldn't slip back to a minor power.
- Get the Italian Minors in your custom union (see below).
- Grow your economy as quickly as possible by focusing on minimizing construction costs and goods that you have a comparative advantage to produce. You'll want to avoid deficit spending since the surplus will be needed to expand the army and navy.
- Get a trade agreement with France. Even better if you can get a defensive pact.
- Improve relations with any nation that has an interest in the Italian Region that isn't Austria or Two Sicilies. Particular attention should be put on the UK, Prussia, Russia, and Ottoman since they are the most likely to intervene. The former two are also likely to help in a play.
- Expand and modernize the army and the navy.
- Reform-wise, you'll want to weaken the Aristocrats and empower the Industrialists. Another goal should be to enact Free Trade and Laissez-faire, which in conjunction with the Mutual Funds tech, will massively increase the investment pools meaning more construction centers and more economic growth.
Union with the Italian minors (Lucca, Modena, Parma, Tuscany)
The goal is to bring the 4 Italian minors into your Custom Union as quickly as possible. Speed is of the essence since the Austrian Custom union will grow to make it more difficult to bring them in. Even worst, those nations could accept to become the protectorate of Austria removing any chances of getting the unification trough the event. It is therefore imperative to improve relations with those nations from day one.
If they have a neutral attribute or better, improving relations and giving them an obligation should be enough to bring them into your custom union. Don't worry about the obligation, they likely won't do anything with it. At worst, an event will trigger where they ask for something minor like a general in exchange for the obligation. If the obligation is not enough, start a bunch of trade routes with them with a focus on the number of goods being exchanged to increase their likelihood of accepting.
If they are hostile, as Tuscany tend to be, you'll want to keep improving relations until their attitude change. Getting Central Banking somewhat early can help since Bankrolling them will increase the cap at which relations will go. It will also randomly provide an obligation that you can forgive for an extra 30 relations.
Having those nations in your custom union and keeping high relations guarantees that they will join through the unification event pretty much as soon as you reach the major power rank.
First step unifying Italy
- At this point, you should be a major power so the event to annex the Italian minors in your Custom Union should trigger shortly. If any of them aren't in your custom union and are not a protectorate of great power, it's time to look at your options. I would not rule out to keep trying the diplomatic route since the event generated quite a bit of infamy making the military route riskier. The AI also tends to reevaluate its attitude around the time I reach major power status which can turn a hostile nation into a friendly one.
- Dealing with the Pope: Based on my experience, the Pope tends to be neutral or to be threatened by the Two Sicilies. If they are friendly and supporting you, just keep relations high by trading with them and setting up diplomatic pacts to ensure that continuous support. If they are neutral, puppeting them militarily is the cheapest option infamy-wise.
Dealing with Two Sicilies and Austria
With Northern and Central Italy supporting you or under your control, it's time to deal with Two Sicilies and Austria. It's hard to provide exact steps to follow at this point since it will highly depend on the overall diplomatic situation and on how Prussia is doing. Here are some general tricks that helped me deal with those two nations:
- Declaring an interest in Southern and Northern Germany will open up the possibility of getting an offer from Prussia to join a play against Austria in exchange for Lombardy or Veneto. Just make sure the war is not hopeless and that France won't be joining on Austria's side. There is no way that you can survive a two-front war against those two nations.
- Getting a great power ally is pretty much mandatory to deal with Austria and makes the Two Sicilies trivial. Do not be afraid to hand off an obligation to great power in exchange for a defensive pact of an alliance. France in particular should be the one you want since they have the means to help you against both Austria and the Two Sicilies while not having any territorial conflict. If in a bad spot, don't be afraid to sell out to Russia, Prussia, or the UK to get through a tough diplomatic play.
- Having naval supremacy against the Two Sicilies can make any war much easier. Just hold central Italy and do a naval landing in Sicily to make Garibaldi and the thousands proud. If this fails, you are up for some attritional combat in central Italy. Just use your fleet to raid their convoy and watch their economy crumble.
- After getting the leadership from the Two Sicilies, it's worth trying the diplomatic approach to get them to support you. Improving relations + bankrolling + forgetting obligations can do wonders to get them to shift their attitude and gain their support.
- Be on the lookout for opportunities. Third-party nations that have an alliance with Austria or the Two Sicilies can lead to much easier wars.
- Manage your infamy carefully, going overboard can make your ally drop you thereby losing you an asset.
- It's cheaper, infamy-wise, to liberate Lombardy and Veneto and then get them to join through the unification event. It also lets you spread the infamy over a certain duration lessening the diplomatic hit taken with other nations.
