I definitely agree with the power of Sushi. On any map with enough water, it gives you lots of extra food (and culture, which is great in border and newly captured cities).
My corporation strategy is to try to found Mining Inc (1st one available) first, then Sid's Sushi (Medicine is good for growth anyway). I'll focus my great people cities on engineers and merchants in this time period, or if I was lucky enough to get and not need to use (Economics for example) one, I'll save it to be certain of my shot at these.
I'll generally put both into my Wall Street city. It is possible that, in the long run, I'll have more foreign branches of my corps than domestic, but in the beginning with these two I focus on keeping them at home exclusively. The AI will hoard resources if it gets these corporations, so I don't spread them to the AI.
The others get founded in some other city. It doesn't matter too much, as all cities with the money-enhancing buildings are otherwise equal. Still, if I have a holy city which isn't otherwise anything special, I may use it to hold a corp HQ simply to put all my extra-gold eggs into a few highly defended baskets.
Since both of these compete with the others, you can't put three HQ's in a city with them in. The main reason to want to do that is to maximize the Wall Street profits from your widely distributed corporations.
For my foreign corporate expansions, Standard Ethanol and Aluminum Co are good first picks, unless I absolutely want to stifle a competitor's access to oil and aluminum. If they have it, and they usually do, it doesn't help them that much to have these. But because both are later-tech corps, I'd hate to focus on trying to get them and exploit this as a major moneymaking goal in most games. The obvious critical use for either of these is to get the resource if you can't get it via trade or war.
If I get them, I do try to spread them to the AI. The AI will, at least for now, happily drop executives all over their cities once they get a corporation. The new patch may change this behavior, though I'm betting it will continue because corporation maintenance will be lowered.
Cereal Mills and Creative Constructions are my picks for "export" corporations. The benefits they give aren't amazingly good, and while they do both compete with Mining & Soushi, they don't lock out all of the good tradeable resources doing so.
The ideal plan with both of these is to seed a few cities with executives, then let the AI spread it around. Makes the investment much more effective that way. The AI won't do that if it runs State Property, which is a good reason to use the UN to force Environmentalism on everyone. Now for sure, it makes your own corporation costs higher. But if everyone else has your corporations popping out branches right and left, it easily makes up for that.
Civ Jewelers is a tricky one. Unpatched, it is only worth delivering to the AI, because maintenance consumes the money it makes. Using Solver's unofficial patch, it is a pretty good one to have to make loads of money. In which case, it is hard to spread it around much, except for cities where you don't feel a need for the Mining Inc production bonus. If you do that, try to put Sid's Soushi and Creative Contructions into it.
However, I still favor Mining Inc, because of the high potential bonuses on most maps. An extra 20 or more shields in every city, especially the new low-production ones, is useful in all circumstances. And if you do need money, just have a high production city generate wealth.
