I just finished my GP Skybolt with Saito .91 and Replacement tail wheel assembly. I agree that this thing builds tail heavy. I used pull-pull on both rudder and elevator as well. I moved the engine up about 1/2", added a fiberglass cowl + moved the servo tray up quite a bit + put the battery in the nose AND I STILL HAD TO ADD WEIGHT!!! IF I were you, I'd really focus on that tail in keeping it light. Other than that, it's a showstopper in the air....totally beautiful. Total dry weight came out to 9.6 lbs....just so friggin mad I had to add nose weight....maybe on my next skybolt

Here are some pics of mine:



And the tail: