Unless you are bringing particularly heavy items, or particularly densely, volume will hit you before weight at the airboss size and 25lbs. You could go marginally larger with less bag structure and use packing cubes for a similar amount of weight.

You said "We" is this 1 bag per person, or are you sharing? If you are sharing, it will take light packing effort to slim your list of items down to fit 21-22lbs.

If you've been waiting for an excuse to buy one, go for it. I'm sure it will work fine. If not, it's not really designed for this type of trip.