Boarder Line Low Oil Pressure

It's running 10-12psi/1000 rpm, so maybe 25 psi at 2000rpm. My slant six (build by Doug Dutra) had 70 psi cold, 50 psi at 2500 rpm, and 30 psi at idle hot, but he built the oil pump and we used like 0.004" on the bearings when we built it.

I'm less and less worried about this pressure, seeing that it is very common in these magnums apparently.

It's just weird that it is really good pressure when cold, at all rpms, but drops so much once warmed up. Again, I may swap to 20W-50 when I change the oil next, just to see how it behaves. I'm not too worried after reading up on this and getting feedback on this forum.