The Norgren R17-801-RGSA regulator I am using on my system has massive ports and 480 c.f.m. rating.
The inside diameter of all the components in my system are as large as possible for maximum flow. The two restrictions points are the 3/8" flexible hose / check valve coming off the compressor head and the [url=https://www.trainhornforums.com/showpost.php?p=71421&postcount=5]3/4" NPT short thick-wall nipple connecting to the tank, where I step it up to 1" NPT, then 1" Type L copper.