Air/ fuel tuning

I've always had better luck using half of my cruise vacuum for selecting a PV. My 340 has 10.5" of vacuum at idle in gear, but cruises at 18". For me, an 8.5 PV works the best in my 4779. Any lower than that, and it goes lean at tip in. Sure I can bandaid the lean tip in by fattening up other circuits in the carb, but then it's fat everywhere else.