RE: Stepping up to 90 size
The first time I flew a 60/90 sized plane I went "WOOOOW!!!" it was great fun, the plane flies so much better. However, it will not like to be treated like a 40 sized plane. Try to do some nonsense and if you lose speed you will stall her. They like to be treated with some respect. Not much harder to fly (generally) but it will not mess about like some 40 sized low wing entry plane. GO FOR IT!!!