RE: From Trainer to Stik
My second plane was a Stik. Set it up for the low rates and have at it. I found mine easier to land than the trainer and it had no faults . . . though you have to fly it every bit of the way. That one was lost to a mid-air (* sob *).
I went two seasons flying year-round and weekly through the summer - probably 150 flights - before I switched from my trainer and after "borrowing" a few sportier models to get a feel for them. 20 is still too early to switch to a Stik unless you're on a buddy box or have a fast instructor who can bail you out. Mine have all been tail-draggers; probably a trike would be a bit easier to take-off with.
I always expect to have a Stik style model in my hanger (just assembled a Goldberg Hot Stik and will maiden her this weekend - basically a Stik with more control surfaces. Like the Ultra-Stiks). The Kangke SK-50 is just a Stik with a bit of streamlining and would be a good choice also. Sometimes you want to do and try things that a klunky but spunky little workhorse will handle and shrug off.
THE plane for float and ski flying. They make excellent test beds for trying different engines and control mixes.