I would say your pretty much at your max compression on pump gas. If you wanted to step up to race fuel 185 psi and iginition timing of 6-8 deg.
I ran 150 psi on 19cc's I thought it might be low for the dome size. I never got to check the squish before I switched cylinders and added a 4 mill crank.
I dont know what you can run on av gas. If your going to go through the hassle of buying special gas just get the real deal. Leaded fuel is fine. I run Citgo 110, or Sunoco Standard 110. I have also ran VP Red (105 motor octane) on 185 PSI, +7 deg timing on my stock cylinder 4mill. VP fuel is way more expensive than the other race fuels out there.
josh