ORIGINAL: carrellh
I have a GP Big Stik 60 with OS 91 four stroke. I've only flown it a few times and it's much more maneuverable than my trainer. The first flight, I thought it was "too much" on high rates so I programmed low rates and exponential for the next flight. It was much better (for me) with the milder setup. My brother (who has a half dozen planes of various flavors) flew it with everything maxed and liked it set up tht way so there's plenty of room for me to learn with this plane.
I think any '60 class' two stroke would be fine for this plane. I had the four stroke in the drawer so I used it.
Ideally, I think I would like my next plane to be sized for this engine:
[link=http://www.horizonhobby.com/Products/Default.aspx?ProdID=EVOE1100]Evolution 1.00NX[/link]
Of course a lot of planes seem to call for a .90 or 1.20 but not 1.00.
When we were in the hobby before, one of the parts I remember that I did not like was playing with engines to try to get them tuned correctly. I also did like breaking them in by running a few tanks of gas through them.