That 800 is probably undersized for your combo so it is probably going to cruise on the mains. The Double Pumpers are competition calibrated carbs, so the cruise will be fat. You may start by stepping down 4 sizes on the mains to get a feel for how far you will need to go. And if it does cruise on the mains, the PV opening point will not need be as quick as it would if it cruised on the idle circuit. But having said that, I personally like an early opening PV. Better a bit rich that a bit lean on the transition. No stumble or hesitation that way.