advance

The quench should be helping you. A huge part of the equation is the mass the engine has to move. You're making it easier: light weight, with gear, and with convertor. So bring it. Watch the plug porcelain with a lit magnifier for any signs of piston material. Also be aware of carb tuning each time you make a timing change. You don't always hear a problem. But we run 91 crap with 10% ethanol in the ground here.