Pete, first, honored to be able to give you any input whatsoever. Your credentials (and Curt's high praise) preceed you.
I owned one that was 58#@27...at the time, about as heavy as they would go. It is a superb bow, imho, one of the top two bows I've ever shot. I certainly think it's efficiency would be capable of taking and elk at the draw weight you are looking at. I've never killed an elk with a bow, but I think hogs are pretty tough critters and have taken a few of those. With a 650+ arrow and the right head, I would have taken that bow against any hog in the woods. As you saw from your own tests, the ACS/CX's poundage belies it's efficiency.
While I don't shoot as heavy as you, I do prefer the heavier weights. If A&H would intentionally make limbs well into the 60's that I prefer to shoot, I'm not sure I would have sold it.
Imagine what such a bow would do in the 70# range :eek:
Good luck; in short, I don't think you will go wrong with an ACS/CX...it just may take some getting used to at a weight 15+ pounds less than what you are used to shooting.