You've asked a question that I too have been pondering for a while!
I'm a former army officer (and UAS pilot), who seriously got the flying bug only after I had passed the maximum age for aircrew in any of the services, so left the regular army for the TA and then qualified as a civ pilot. I'm hoping to join Air Tanker - but like you I wonder whether there is really any possibility for non QSPs like myself. Even if I were able to join, would QSPs just sneer (which most do at civ pilots) or would I just be regarded as an equal (which my army peers regard me, despite my now TA status)? Incidentally, I am not the slightested bit interested in how the pay compares to the airlines - I want to do it for the right reasons.
I guess the only way to find out is by applying - but interested too to canvass views here.
Beags - why would AAR be a problem for a civ pilot? I bow to your superior knowledge - but is it really that difficult to learn?