Tune completely with vacuum off. you will be able to use 93 but get summer 93. yours may not vary as ours in the cold north! work the mechanical advance idle and what not for a few weeks to get the best total 36 to 38 produces best HP and to get a good idle 900 to 1000 in gear with 22 or so idle advance. tune till till you have no ping under any driving conditions
Once you are happy and have not made changes in a couple weeks??

Then and only then you can if you must plug the vacuum advance back in to ported vacuum.
I would expect light throttle ping to come back at this point! so with a 3/32 allen wrench in through the hole in the dis vacuum port you start tuning out that ping by turning CC. I would go 3 turns right off the bat. drive and keep going CC till you have no ping under any driving conditions
(I personally think the vacuum advance has no place on a performance car especially with todays fuels)
By the time you tune out ping it does little anyways. If you were to adjust timing with it hooked up now you would lose all your WOT performance???