Yeah, well, for $100 you don't get Osprey packs. Packs are always a compromise between space, weight, and price. Given your requirements, and knowing how camps budget their funds, I'd sacrifice weight. After all, it's unlikely that you'll be using these for extended (five days or more) trips where weight really becomes more critical.
If it were me, I would take this question to the nearest REI store and ask them to make you their best deal. You'll get decent quality, a reputable store that will take returns, and the advice of someone who is used to fitting packs to a lot of different people and bodies.
There's no easy answer to this one, so plan on making a few compromises, and getting some packs that at least a bunch of people can use for a few basic trips.