I just used a Cascade with close to 30kg, only over 2 days and it carried that weight remarkably well. There is a lot to be said for a robust design even if it weighs a bit more than it's competitor. I have no experience of the Osprey, it might be perfect for you.
As I was on a work trip it meant dropping pack unloading and reloading the pack up to 20 times each day I was surprised at how little the pack weight was of impact despite a frenetic schedule.
Please share a trip report, I would love to do an extended trip in the Kimberley, and no-one on this forum has shared one from there yet.
