The distinctions can get rather blurry; especially with the several excellent 1.20 two strokes available today.

With the 3D guys hanging 1.60s on a model that would fly fine with a .61 (and telling everybody about it), things can get even more confusing. And the so-called "tweeners" are in a class by themselves. These are slightly-larger-than quarter-scale aerobatic semi-scalers that are "between" large glow engine and small gasoline engine size. The Goldberg Yak (77" ) and H9 Extra 260 (78" ) are good examples of this.

IOW, your best bet is to ask advice regarding a specific model. Not trying to be obtuse, but that's the way I see it...[sm=drowning.gif]