Still no Tom????

I appreciate the suggestions so far, but I'd also like to know what the firewall is set at by design to verify that I don't have a problem with that as well as to get Tom's perspective/experience on what works. Offset can be affected/determined by engine and prop size, so this is running a 50cc engine (no I'm not going to say which one) swinging a 22x8 Mejzlik at 7200 RPM for our altitude.

I realize it's very much a process of trial and error, but a 1 degree change in the offset is a HUGE difference. FWIY, I chickened out on the 2.5 degree offset based on the idea that there's no way it could have been that much to begin with as the difference in the washer thicknesses should only be able to change the offset by 1/2 degree in my experience. So I set it at 2 degrees of offset and put it back together.

I can still save myself some time/effort if someone's got some data on this? Flying days around this neck of the woods are getting scarce now until spring, so I'd like to make best use of what's availble for the next three or four months...

My thanks to all who've responded so far!