I would opt for the 1/4 inch brass but will that flow enough fuel with the
dribble low pressure system?
I am assuming that I need somewhere near 18/20 GPH at 6000 RPM at 3/4 LBS
pressure.
I'm trying to make a needle control valve, feeding six .065" nozzles in the
intake of my six port slide throttle for the Renesis.
Also, what fuel pump are you recommending?   Karibian

I would go with the MSD positive displacement. The Walbro type have
trouble sucking. They work well inside the tank which is where
they were designed to be used.