I was swinging an APC 15x8 at 9500 RPM (10% nitro) while my engine was breaking in, and it was puh-lenty for Sportsmans. I think it's safe to say that power was the LEAST of my concerns! I have the 120AX and had to add something like 2 1/4 oz to the tail (although I do have a forward mounted throttle servo), so the weight savings up front will be good. I have room to move the engine aft and I might do that later this year or next winter, but the point is your plane should be 1/4lb lighter than mine. I tried a 15x10 to start and it was really nice, but my new engine took too long to reach RPM with it and acceleration was a bit slow. Of course try some different props to see what you like best but I think you will be fine with that .91.

Tower sells the Venus II combo with a TH .61[8D]