Ok, after a few shipments I was able to try some comparisons and nothing seems to be working.

I tried two starters - Hobbico 90 Deluxe starter, and Tower Hobbies 180 Heavy Duty Starter. I tried both starters with a fully charged Power Core battery (12v 1.2a lead acid), my car battery (12v, lots of amps, lead acid) and two 7.2v 3000mah nimh wired together with the above connector.

None of this is enough to start my 120AX. Sometimes, with even the 'weakest' setup, I am able to do the 'running start' and hold the starter against the cone for a full revolution. and once out of 10 tries I was able to get the prop spinning enough for multiple cycles.

I guess I need to try a different style starter?

Boy am I having growing pains...starter issues, pull pull issues....OOOOUUUUUCCCCHHHH!!!!