Basically, I have one large backpack and if I end up going for a much shorter trip, say for 3 days instead of 2+ weeks, I am going to end up with empty space in the backpack.
From a stability and comfort point of view, am I better off leaving the side compression straps completely undone until I am completely packed resulting in a pack that is short and fat, or should I pack it with the side straps partly taken in so that the backpack ends up being taller and thinner?