Stay away from 60 sized engines if you can. The extra weight is not worth it. I have tried this out in a few 40 sized planes for aerobatic flying and its no fun. If you want to have fun for 3D etc then go with something like the Saito 82 or YS63. Is there a Saito 81? If you mean the Saito 80 then between the 80 and 61, weight is no longer an issue as that is all you have and both are about the same in weight.

ps the Fliton Extra 330 is a real superb machine to fly. Tried it with a Saito72 and TT61 2C, the Saito 72 was more fun to fly than with the TT61.