ULA Ohm for Philmont

I'm looking for a new pack for our 2010 trek and was considering the Ohm, but was wondering if it would be big enough for a Philmont trek. I've been moving toward lightweight and while I'm not quite there yet, I will be by Philmont. My current base weight is around 18 lbs, but I targeting sub 15 lbs by next year.

We're planning on using very little of the Philmont gear (only bear bags), following a lot of the ideas on BPL. Thanks to Doug Prosser and others for all the knowledge sharing.

I know a Circuit would work well, but I'm concerned that it will be too big a pack for overnigters or other short trips after Philmont. It doesn't seem like it's able to reduce volume for smaller loads.

Thanks in advance,
Gregg