After all this talk, talk, talk - I thought "maybe I was wrong?".
Took the Naut out and filled it.
After 10 minutes the darn thing still hadn't primed.
Emptied the tank.
Put it back in the "junk" bag.
Back to my Vision Vivi Nova's.
As Rube Goldberg found out the hard way - the simplest devices are usually the ones that work best.
My local B&M told me to take 5 long draws to the count of 10 without pushing the button and with the air set to the second hole rather than just giving it time to prime. It's worked great for me following their advice.