It should work just fine with the P90. If you want to though, I'll send you a flange before you pay for it so that you can check the fit of everything.
All I have here are N47 heads, which is what I took my measurements off of.
I've got the intake flange design complete. It was my plan to make an ITB setup, but I could also get additional flanges cut for you guys. What is preferred, aluminum or steel for your purposes?