Regardong the engine for the GP Skybolt. The first one I built had an OS 1.20 Surpass II. The second one had a Saito 1.50GK.
Both aircraft required the heavier engine more for nose ballast rather than for required power. In answer to your unspoken question, No, I don't normally build heavy. After 10 plus years of building competition gliders before entering the power plane arena about 20 years ago, i usually only build to fly, not crash.

Silversurfer