Got something else done, since me engine is elsewhere at this time. My intank inlet lines. 1/2" ID throughout, except the bypass valve which is the first thing in line. It's .040 under 1/2", so I'm going to let it slide.

Where the inlet/bypass valve will be residing, right beside the hole that lets fuel into the bowl-thing.

I've got 1/2" air line going to my LP, then I haven't decided what to do with the outlet of it. I'd like to keep it at 3/8 ID, but I'm going to have to look around on ways to do it. The factory outlet line is some kind of flared setup, with an ID of 1/4". I don't really want to clamp a hose on it if I don't have to, since that'd leave me with a 1/4" restriction no matter how big it got from there.

Just to edit, the HPLP outlet threads are M14x1.5 and the VE inlet threads are M12x1.5 o-ring. Dunno if I'm going to make something myself or what yet... I know I want to keep the ID as big as I can.