I've learned that, if a wet tent is a possibility, I prefer to put the tent into two smaller stuff sacks. The fly is usually a lot wetter than the inner (at least for a few days.) By storing them in separate sacks, you prevent the wet fly from making the inner tent even wetter, which means you've got a chance at it being a little dryer the next time you pitch it. (On packs like the Osprey Atmos and Exos, some of which have divided outside pockets, you can do the same thing by putting the fly in one pocket, and the inner in the other - saving the weight of two stuff sacks.)