I don't know what all thread you have seen on the pickups in the pump modifications. So here is a link to one that you might find interesting.
Small Block Oil Pick Up Tube Question
there are a couple others that I would add to this as I find them.
Found on page 3 of this thread.
Reworking the 273 Adjustable Rockers
For information.
The crossover tube that you install is feeding the driver side from the passenger side. Which in turn is feeding the number one main and the number one rod bearing. Along with the lifters on that side.
On the oil pump pressure you keep saying high volume low pressure.
The standard 72 pump and the high-volume 72 pump use the same bypass spring.
