Hello,
I built, cloth covered, painted, and installed a Moki 135 on a GP Super Skybolt for a local fellow. Not my engine choice, I do what I am told. Nonetheless it was a fine flying airplane with no bad habits at almost 10 pounds. It required no nose weight to balance. What an awesome plane to watch fly.
If you are sure you want a gasser, hang 3 pounds on the nose and check it out. That is what my RCS140 weighs ready to mount. It almost has the power of the Moki 135...almost. But it definitely is heavier.
Tim