For those who find an under-packed A45 more comfortable, how are y'all packing it? I've tried 1) distributing weight evenly along the entire bag; 2) putting heavy items in the bottom pouch; and 3) leaving some weight in the bottom pouch but strapping most weight in the middle compartment...but in all of the trials, the back panel of the bag sags/bows away from my back to varying degrees, which makes it feel far heavier. Has anyone else experienced this problem?