Good advice as well, and why you should use a gas can then keep moving backward with what hose you disconnect and stick in the can.
The vapor locking is a good one to try. And I would in hopes it's not what I think it is. (You have no idea how much I want to be wrong on this).
I'm still convinced you have a deeper issue, yeah the tanks and pickups/tubes, the hardest thing to deal with of any scenario I know, and just what you DON'T want to hear. But you've checked and replaced all the hoses (Which are the same size I'm running on a dual 750 Tunnel Ram and Terry admitted running on a Blown twin Dominator V-drive, more than enough!), you've tried two different pumps, 1 mech, and 1 electric with basically the same result, so.
Bring the thing to Big River friday, and I'll ride with ya and when it dies, we'll open the fuel fills and see if that cures it. If not, well I'm right. If it does, FANTASTIC, easy fix, vents are plugged or add bigger vents, easier than pulling the tanks!
(I was told I had a vapor lock issue in the Blue Meaney. Don't think that was quite it, given the result, More later on my theory on that ordeal, but I think it's related to your troubles, lol).
Ray