Id try 5psi and go from there. The 4 snows are kinda like pro wedge 2's. We warned, if you make a good bit of power, they actually arent too good.
My CST Pulse hook much harder than my pro wedge 2's. And my CST Pulse are much heavier and are on a steel wheel vs my pro wedge 2's being on a thin aluminum wheel. Go figure. If i was serious about getting the most out of my bike, id toss the steel wheels and my gforce axle in the trash in favor for a JJ7A light weight solid play axle and some light aluminum wheels. But, that isnt needed right now.
It's hard to see here but the tires just ballon and the bike doesnt move forward. The +6 swing arm is working against everything for acceleration (read as traction) though.