RE: YS 120 Size 3D
Yeah. A good plane to throw that on would be a Sig Sukhoi SU31. This is an Arf and is able to be built in like 48 hours. Or if you are looking for a real aerobatic 3-D type plane for that I'd go with a 120 size Ultra Stick. Trust me you'll have some fun with that! I always wanted a full size Ultra Stick, but I need more channels and more servos. Lol I only have a six channel radio. Anywayz all I run is 4-stroke engines. Either Saito or YS. Yeah that YS 1.20 engine you have will do great with anyone of these planes. So take your pick.
Marvin....