I had the 2.38 alone with stock heads and cam and no slip. I don't see any debris on the belt, but my boost drops a couple of psi at higher rpm, which ive seen people report as efficiencyYes that's the plan. If the boost happens to be to high I'll just move to a larger supercharger pulley.
Do your remember how much boost you were making before the cam, ported heads and 8.6 lower? I'm just curious.
If you haven't already, check your upper pulley for dust and debris. That's usually a telltale sign of belt slippage. I''m using the same Griptech as you with a green belt and no slippage so far.