What size Stainless fuel lines would be good for about a 600BHP engine with 42# SVO injectors @ 43.5psi?

I run 800(flywheel)HP, including a 300-shot of dry nitrous off a -6AN supply line (similar to the 3/8" stock diameter on the supply side) and a -6AN return line (just slightly larger than the stock 5/16" return line). I'm running 78# injectors. The only thing that's different is I feed the supply lines into the back of both rails, and take the return line off the diagonal cross-over tube at the front of the rails, then to a Weldon AFPR mounted under the cowl.

-8AN feed and -6AN return should be MORE than enough.

-B