RE: Setup for OS 91 VR-DF Fuel/Plug....
I agree with the MC-9. I always ran Omega 5% and added 4 oz's of Klotz synthetic racing oil to a gallon of fuel. This oil is usually found in hobby shops in a quart bottle. I could get 10-12 flights on a single plug, and the only reason I changed the plug then was because I thought that was enough flights for a plug under that kind of stress. Good luck!!
Mike