The answer is clear, just remove .010mm shim and pay a look on the carb adjustment. Maybe you need to lean just a tad the LSN and the HSN.
You don't say which engine is an their size, but if you're running a 30% on a Nova .21 I would go to around 0.50 - 0.52mm of combustion chamber height (measure it with the crushed solder wire method). The same applies for a Ninja .21 engine.
You can go lower, but... you need to have guts and be ready for facing runtime problems, bitch carburetor adjustments (more critical) and maybe a rough but powerful engine.
[quote=MugenDrew;2684554]BATTERIES are for FLASH LIGHTS, gasoline is for cleanin parts, alcohol is for me to drink and well NITRO...everybody know thats for racing.[/quote] :D:D:D