Vacuum advance is for part throttle driving to give more advance and better mpg. Full throttle(near zero vacuum) the canister does nothing.

You don't need to use it if you don't want. Total timing will not change during full throttle. Try tuning without it then try to add it later on. You can also adjust them to change the amount of vacuum is required before it starts adding timing. Just use an allen wrench in the small hole, sorry forgot the size.

With a bigger cam (granted your pulling a fair amount of vacuum) the power valve in the carb can really screw you over on tuning for a nice idle.