Fine Tuning a 360 Magnum with a Brawler "Double Pumper"

So on a normally setup DP, half throttle is just about 75% or so open on the primaries right? Give or take.

If I’m feeling it right, I think I can tell in the pedal when the secondaries are about to open because the pressure on the gas pedal changes, feels like the cable gets stiffer (the linkage getting ready to move on the secondaries). When I’m cruising at 45 in high gear on flat ground and I get on the throttle, this is around the point where I can hear the engine start to bog/sputter (which happens at about 10-11 inches vacuum). Does this mean I should still be looking at a 10.5PV?

I would imagine this would overlap with lower throttle input on a grade with payload or something. Or is that going to be way too much enrichment too early, and I would not really be able to easily tune a true WOT scenario because the PV is dumping its fuel early