I run 20% cool power MV(multi-viscosity) at 500' ASL. I also was in the same boat as you, I considered the YS-63 and found someone who had both and they liked the Saito 82 since it could swing a 15X4W well. I now own 2 saito 82's. Plus I'm not sure about the 63 but you cant get a YS 110 right now and probably wont for a while. YS just doesnt produce a lot of engines. If you already have a 90 size 4 stroke I would use it, Mine weighs 6.5 lbs.