I'd aim for 1mm overall, wasn't so keen on the TLDI gasket option as they don't tend to last so long seemingly. Haven't run one myself so can't say for sure.
Another thing you can do is raise the air intake section on the cowling, put some washers in to change the angle and get more air in. Always thought it would be cool to have an intake on the cowling that opened as you twisted the throttle but maybe a bit ambitious!
What prop are you running at the moment?
Cheers, Seumas
Apologies only just seen this. Stacks do make a difference, help get a bit more airflow into the engine but obviously they are less waterproof than a standard airbox. Best improvement in power is from skimming the head, the general number for a tohatsu 50d2 is 1mm, increases compression by 30psi and can still run pump unleaded. Will give you more power throughout the rev range, more torque too. If you're removing the rev limiter you want to weld the crank, then the engine is strong enough that you can really extract more power from it safely
Cheers
