Ashmeads and Golden russet are said to be kind of shy bearers, I have heard that Roxburry Russest gives more fruit, you only have a few trees so you want to maximize. Liberty is also supposed to be pretty good for cider, havent tried it yet but have some planted. Good on the Grimes Golden, we have a few and I think I am looking forward to tasting an apple from my own state very much. Wickson also a good crab apple they say for cider.
I think the American style cider can be higher in acid, the euro guys call apples with more than 0.45% acid sharps, that doesnt even begin to get in the wine range for white wines which can easily be double that and if you get a lot of acidic apples, I think the higher acid apples go just fine with a little tannin like from crabs.