the real reason you last number 4. ran the stock fuel rail.

I'm pretty sure its been proven time and time again that this doesn't matter?

Single feed rails rob the 4th cylinder for gas, equal is always better

Given that there's 60psi going through the rail I do not think it matters. That's a lot of fuel.

Let me rephrase. I'm like 90% certain there is empirical evidence that invalidates your statement.

If faeflora with 92637 horsepower isn't worried about it, I don't think it's an issue, unless maybe its a full blown track car.

Regulators, how do they work?

Hydraulic pressure is equal everywhere in static conditions (fuel flow on the order of what we're talking about is relatively static, so flow losses are minimal). No cylinder would lean out more than another, even if the fuel rail were losing pressure. Also, I think the return is on the side of the rail closest to Cylinder 1. Your logic doesn't follow pman.

My FPR is at the back of the rail by cyl 4. That's where the return fuel leaves.