Just got done tuneing carb

[76bonanza]

got vac guage and tuned carb, 12 deg advance, idle about 700 holding about 21hg on guage has a slight drop of about 1/2hg every now and then should I worry about it?

Also I have my dist on ported vac and lots of people say I should run it on full vac when I do it pulls it into advance at idle is that not bad? Just dont want to kill anything and I dont know how worn dist. is will be getting a new one soon(old one is squeeking really bad).

Thanks