If you're insistent on running regular you can still raise the compression 1/2-3/4 of a point safely. Again, you'll find an improvement in throttle response and should feel an increase in low end and lower mid range torque, which will translate into slightly better mileage (if you can keep your foot out of it).
I take it you're going for the Panchitos with the cnc'd combustion chambers?
Originally, yes. But after reading your advice, I'm considering switching to the 54cc chambers. Losing 7cc pushes static CR to 7.87:1. If it knocks on regular, I can always buy mid-grade. and a little extra mileage never hurt anyone. Who am I kidding? I've never been able to keep my foot out of it!