I think that for the desert hunt you shouldn't need anything much larger than a day pack (3000'ish ci), assuming you won't be needing much away from camp.
For the AK and BC hunts you'll obviously need a much larger pack. I've never spent longer than 10 days away from base camp on a mountain hunt, and I've never been on a guided hunt, so take what I have to say with a grain of salt. If I'm going on a 10 day hunt with a partner that's splitting some gear, ie., shelter, spotter, cook system, etc., I can pretty easily get everything into a 6300 ci bag. If I'm doing the same hunt, but solo, it takes at least a 7400 ci bag to fit everything, and then I'm maxed out as far as space inside my bag. The ability to use the load shelf on packs like the SG can be a huge plus, but it may not necessarily be something that you need (at least for the pack in), if you're being guided.