bigger is better as long as they are both trainers. the LHS uses a huge trainer that spans 90" with a fuse nearly 70" long. the plane is rated for G23~26 but he has a 45cc gasser from china on it.

because it's big, its slow and floaty
because it's big, it's easy to see
because it's big, it takes a LOT of wind to phase it
because it's a gasser, i've never seen it deadstick

the lhs owner, who's the same guy who has the jet-powered GeeBee, is a loon. here he is hovering this trainer...