Yes it will fit vertically inside just fine. I just test my Weekender in my Gorilla and you actually have a little extra room all around the canister. I plan on putting my sleeping bag, down jacket and sleep clothes in a poly bag on the bottom. Then place the canister on top of the poly bag. I should be able get my MLD solo mid/bivy beside the canister and probably something like a rain jacket. Then more gear on top (i.e. stove, stuff sack with misc gear, etc).