Hmm.. I've never used 10% and dont fly with anyone who does, nor do I have any experience with Webra engines. Small group of guys I fly with use 15% for the OS .50 engines and a couple (including myself) run 30% with the OS .32 and .37. I'm not saying 10% is bad I've just never used it.
If you turn the mixture valve clockwise that should lean your mix...try running richer (counter-clockwise) and see if you get any improvement on power and temperature. I dont think you can compare a Webra to OS in regards to tuning but just FYI I run the mixture screw on my OS .32 at around 2 full turns out. Do you have the manual for your engine? If not you could prob find the info needed on Webras website.