How much total does it have (not counting vac. adv.)? Is it all in by 3000 rpm or less? How much advance is the vacuum advance giving you?
Another thing that is often overlooked, is if the cruise rpm is less than the rpm where the mechanical advance is all in by, the vacuum advance has to make up the difference to get the best mileage and drivability. If this is a w/e "toy" then maybe mileage doesn't matter. But it may have a better 'feel' by using enough vacuum advance to get it up to at least 45 degrees BTDC at cruise rpm. The only way this would be a problem is if you did high speed cruising and the vacuum advance was set to come in at a vacuum lower than the cruise vacuum. In that case it could be over advanced, but that's where the adjustable vac. adv. can help.