Seth, the vacuum advance really only works "Around town"... it keeps timing earlier during lower rpm, as you raise rpm the vacuum does less and less, higher rpm's are then controlled by the centrifugal weights. When folks say "All in by some number", it means that there is no advance left to give. So if you max the advance at say 2500 rpm, there won't be any more timing input until the rpm's come back down.. say like 2400... General rule of thumb for max advance is to keep it at 30 degrees total. Then once you're sure the combo of air/fuel is good -then move up the total to 32 then 34 if all is working well. You may never reach those top 2 settings as pre-ignition and detonation are easy to induce.