RE: Sig Skybolt engine choice
I have an Sig Skybolt with a Saito 80 with a Slimline Pitts muffler. Flys Great. Had a Saito 91 with the same muffler. Flys greater. Go with a four stroke 91 size. (I have a Hog Bipe with a Saito 100 and I would consider it overkill in the skybolt, but fun.)
Stan