Go read post 11. If you do not understand the power valve system works and what it does, you set the PV timing by 1/2 idle vacuum. I explain it as much as I’m going to below.
The power valve does NOT affect idle unless it’s leaking around the gasket, the valve itself is hitting the boss in chamber on the main body (I see that a lot) or in the very rare occasion that the diaphragm is ruptured.
Mark Whitener posted a you tube video PROVING the PV does not affect idle.
So setting power valve timing (thats what you do when you change the power valve to a higher or lower number...you change the TIME that it opens so you are adjusting that...you don’t change how much fuel it flows, you change WHEN it opens and starts power/load fuel enrichment) by 1/2 the idle vacuum puts a GIANT hole in the fuel curve for no reason other than to do what Holley, and all the gurus have been doing wrong for decades.