Sig's kit quality is superb so I'd go for the Sig 1/4 scale Spacewalker. It's a low wing, 7' span, can do aerobatics and it's a fairly docile slow flyer when that mood strikes. It requires .90 to 1.20 two stroke, larger if you want to use four stroke.

Note: Sigs' tech staff indicated that using a gasoline engine is no problem. This is significant when you realize that the Zenoah G26 (the one I inquired about) is 36 ounces heavier than the Saito 125 I have decided to go with.