Idle way rich

On a correctly running engine the PV has no effect at idle. I have a car that pulls 8.5" of vacuum with a 10.5 PV. Runs no different at idle with a PV plug in the carb. I suggest all the time to get idle set with a PV plug in place. Completely removes the circuit and if you put a PV back in and it runs like junk, something isn't right.

Nuke, You are trying to find the point of best efficiency. If the idle speed picks up, it's more efficient at those settings. Dial the idle speed back down to where you started and give another twist. DO NOT just continue to feed timing in without resetting idle speed. You'll find a point where it doesn't pick up any more RPM.

Find the point the engine kicks back on the starter when hot. That's my preferred method. Another, hook up a vacuum gauge, advance timing and reset idle speed, did vacuum increase, if so do it again. You'll reach a point where it won't increase. Dial it back 2* and then fix mechanical advance to hit your total number.

I tend to do things where it's one method or starter kickback whichever is lower. If starter kicks at 20 and dialing in or vacuum shows 24, you can't get 24 because the starter won't let you.