I use a blue foam pad and like the method of putting the pad in first like a cylinder. Once its all loaded up the gear becomes the pack, the pad, and the gear inside all become part of the suspension system. The only downside is the shape can be a bit clumsy, but it seems to work ok for me with a Jam2 large, up to about 30 pounds. Better at 20 pounds but what isn't. I think a good rule of thumb is a well designed pack should weigh about 1 oz per pound of gear carried.