OK I found the build instructions for the plane. engine size is from a 40 2C to a 72 4C. With my 90 4C, I'm going to set the thrust at 2.5. I was going to chicken out and set it at 2, but decided if it flies on a 40 at 1 1/4 degrees, 2.5 should be good on the 90 4C. That converts to .218 or 7/32 setback on the right side on a 5 inch wide firewall. It looks like a god awful amount of off-set. I can double check it with a roofing square that has degrees marked on it. I still might chicken out and set it to 2 1/4

Thanks for all the help and encouragement!

Ken