906 or 915 ?

I've read any and everything i can find about the 906/915 style port. What I'm doing is quite time consuming so far but thats fine by me. So far I've blended the bowls to 85% of the valve size (2.14/1.88) and im currently cutting/shaping the guide boss. All I've done to the ssr currently is go 90° straight down from the 70° cut. I've been researching laying down the hump, raising the roof and sides to slow the air for the turn. Ill save that for last when I've got all the information I can soak up.