I removed the balance shafts in my 2.6. Cold I see 80-100psi at idle. 25 psi at idle when hot (My idle is pretty low) and cruising down the highway at about 2800 rpm I see about 80 psi. It will climb up to about 100 if I let her rev out. I believe the bypass kicks in at 100psi. The rule of thumb I have always known is that you want at least 10psi for every 1K rpm.
I run 10-30 oil, although last winter I dropped down to 5-30. We had plenty of below 0 deg. F nights, takes an alarming amount of time to build pressure when oil is about as fluid as molasses.