On takeoff, with the temp needle touching the yellow (100F), the oil pressure on my field reman (by me) 0-320 is right at 100 PSI. In cruise, with the oil at ~160-180F, the pressure is 80-85 PSI. In warmer weather, my oil temps in cruise are ~200F, giving oil pressure of 75 PSI.
Back when I was fighting oil temp problems and saw 220-225F oil temps, the pressure would decrease to ~65-70 PSI in cruise.
Hope these data points help. In reality, I've been considering pulling one more washer out of my pressure relief valve - my pressures are a little high, probably robbing me of a little power and magnifying any oil leaks.