I have a Norvel .074 w/throttle flying a Sig Ninja, and have had several 2-meter sailplanes mounted with .049s. I also have a 56" Astro Mini Challenger converted to Norvel .049 glow...I run 3 shims and 15% fuel with a 8 X 4 cox prop at 7500 rpm and it can climb straight up. You don't need the weight and drag of a .10 to loft a 2-meter. .049-.061 is good. A Norvel .074 is almost too much, unless you're flying it as a sport plane instead of a sailplane. If you're using a .10-.15, I'd suggest a 3-meter bird. I once tried a Magnum .10 on the nose of my Wanderer, and didn't like it. It was too much power, and especially too much weight...Totally killed the plane's ability to thermal in the light to moderate lift we have around here.