For me, Z-Packs Arc Blast is unbeatable in its sweet spot which is the 15lb-30lb total pack weight range. At these weights, it transfers weight to my hips as effectively as any heavier pack I've worn. (I've carried up to 40lb for short segments where I've had to carry a lot of food or water – it's quite strong enough for that, but I think 35lb is about the limit for comfort)
It carries any standard bear canister fine. I find a piece of a Gossamer Gear sitpad (about 1oz) behind the canister supports it against the middle crossbar of the frame, keeping it comfortably off my back.
A couple of things to consider if you go with this pack:
(1) Ask Joe to add an extra reinforcement patch on the base, this is the area most prone to abrasion.
(2) The hydration port is the only hole. If you won't use it, omit it (menu option), and the pack is an intact drybag – it comes standard with taped seams. With the extra patch above protecting the base from abrasion, I have one that's been heavily used in rough terrain over a year but is still virtually airtight, i.e. if I close the top with air inside I have to push down hard to expel air.
(3) Torso length is not adjustable once the bag is made – the bag is custom sized for you. It's probably not critical +/- 1" or so, but for comfort do make sure that you measure your torso correctly.