I'm going to go along with the 60 size trainer.

They fly better and are easier to see as many have already said.

If I had it to do all over again, I'd build the following model for my first trainer.



It's a Goldberg Protege. 71.5" wingspan and a fuse that's 65"! It will fly on a 40-60 size engine, but I'd opt for the .60.

Just built one for my grandson and it is one wonderful flier. Easy to build, too.

Just another suggestion for you.

Good Luck in whichever model you choose!