I appreciate all the input guys. Gives me something to think about and do some experimenting with.
I'm a R/C retread from 20 years ago and relearning just about everything from scratch, given all the new technology.
I have been flying C/L for a few years, got back into that while recouping from 6 bypasses on the heart, but I found myself getting a little bored, started with a Park Flyer-Slow Stick, and got bored with that, now I'm building a Sig Midstar 40.
When I first moved to Colorado 30 years ago and then got into R/C, the local guys in the club said go up one engine size and 5% more nitro for the altitude. With the new engines these days I don't think going up in size is that important, but I learned from C/L flying, about 15% nitro helps a lot.
Props have always been a guess and experimenting is the best way to get the proper engine run.
Again, thanks for all the input,
Jerry Bohn Longmont, Colorado