I'll have to disagree with every point you make:
  1. You do not have a successful purge until you have oil pressure AND solid valve lifters.
  2. A gurgle in the tank only means you have pushed all the oil out of the crankcase; it does not mean you have purged all the air out of the oil system.
  3. Air trapped in the oil cooler must get purged out or when the thermostat opens you will get a slug of air into the system-not good. Fortunately the 10% going thru the cooler even with a closed thermostat will purge the air out of the cooler if you give it enough time. Therefore it is somewhat of an issue in purging.