Smaller the rim the better because it allows more sidewall. Most use 16's as far as street legal slicks go but there has been alot of 15's making the scene with drag radials on them.
As far as best I think it comes down to preference. I have a set of MT but will be trying the Hoosiers next.
Does BFG make a DOT Slick? Their 18" drag radials are pretty good once they get a little wear on them.