I'll have to disagree with every point you make:
- You do not have a successful purge until you have oil pressure AND solid valve lifters.
- 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.
- 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.