PV selection depends on what type of driving you are doing. For drag racing it doesn't matter too much since you're at WOT all the way down the track. You can keep the engine from loading up by running a PV on the primary and leaning out the main jets.

For a street car you set the PV so that the enrichment circuit kicks in when it is needed. You have to drive the car to figure out where that is. Drive the car with a vacuum gauge hooked up and see what it tells you.

Nobody can tell you what the PV needs to be in your car since we don't know how much it weighs and what gears are in it and how modified the engine is or anything else.