So very stuck...

Okay, so first off I want to start this by saying I'm not asking to start an argument about which is better "ported" or "manifold". So let's not do that seen to many.

My question: when ported does the motor only use the amount of advance needed? As in when the motor is pulling say 1800 rpm does it only use the amount of advance needed at that point or does it try to use all advance regardless?
So if I turn my can all the way up as the advance comes in will it only pull the advance it needs or will I get the max 15*(on the can) the moment vacuum starts pulling?

My truck really likes the ported side, but I have kept it at its minimum of 8* to be safe and not get pinging. But that means at cruise I'm getting almost 30* should I attempt to push it till it pings and then back off a couple of * on the can?