probably 2 servos for the ailerons, one per. unless the plans use a bellcrank. take a look at some of the build threads for the mustang, there are plenty of them. some have sliding canopies. just remember, you don't want to go too crazy with options on the smaller scale, as it adds plenty of weight, which makes for a poor flier.

http://www.tompierce.net/SBD/html/paint/insignias.htm

this guy put a ton of detail into his SBD, and took home trophies. Read that site for some ideas, but read the whole thing, the ending is interesting, and may help you figure out what detail level to go to.