That's a good read! It says those exact pumps can be used for remote oil systems on turbos, the ratings are max ratings, if you made your own return system after its passed through the charger it will just return to the catch tank, shouldn't really matter on size as it will just keep pumping it round and round? Correct if me if I'm wrong or missed something :S
The psi should be quite high anyway, I mean the oil pressure readings you get at the top of your head at redline are pretty high! So really the pump needs to be the same? For when at high rpm, I would have thought