Andrew,
Turning the engine by hand and collecting the oil delivered by the pump gave:
1986 13B: 426 revolutions per gallon or 11.7 gal/min at 5000 rpm
2010 Renesis: 392 revolutions per gallon or 12.7 gal/min at 5000 rpm.
I haven't tested a pre-2009 Renesis.
As long as you are not using a restrictive oil cooler like those from a stock 13B, the oil will not be returned to the sump by the front OCV during normal operation. All the oil will go through the cooler and the cooled oil will either pass through the
bearings and EC shaft jets or be returned to the sump by the rear iron oil pressure relief valve.
It would be good to verify that your oil cooler is not restrictive. If you want more oil passing through the bearings and jets, you could possibly run higher oil pressure by using a higher pressure rear iron relief valve.
Steve Boese