Wanted to follow up here. After trying a bunch of packs on at the store I found that as mentioned earlier in this thread the Atmos 50 gave me the best fit of what was available. At the same time I ordered a ULA circuit with the plan to return whichever I don't like 'as much'. Since the circuit adjusts via the waist belt and not the shoulder straps like most packs I was able to get a great fit with the pack even though I had to adjust the medium to the longest setting.

I really like the circuit, weight features size etc. The one thing that the Atmos really wins on is the hard frame sheet suspension. The Circuit is the first real pack I have worn without a frame sheet and so it is much more important to pack properly or gear juts out into your back. Still trying to get that right and hoping that if I figure it out my seemingly endless search will be over