Hmm, I usually always climb with 2 or 3 guys I know. in winter, we Always take a Big McHale Alpiner backpack(7lbs-8lbs) we got used, best find EVER! and a smaller summit pack and a knapsack for the guy carrying the McHale or skip it and leave all the gear at base camp and strip the McHale down to about 4lbs, Heavy, but not all that bad either. We switch out who carries the monster load. Best of both worlds. Do the same thing when one guy goes in a day early as they have an extra day of vacation while the other guy has to haul a$$ at a 16 mile clip or more to catch up.
PS. Your Catalyst Pack will carry winter gear with some finagelling with straps and gear tied on. Awkward? Yea, though not after you do it twice or more. Easily doable. Will have to create a foam pad or sometimes simpler is a sleeve of cordura nylon that is put around your ski for attaching skis as skis sharp edges will destroy any lightweight backpack in VERY short order. Attaching snowshoes? No problem on any pack with a couple extra straps.
PS. I will never carry a Gregory, Dana Designs-Mystery Ranch-Marmot, Osprey, Cilo Gear again after carrying a McHale for heavy loads. NEVER EVER!