Other than bottled water, which gets sort of mid carried in my side pockets, I try to keep my weightier items spread out equally inside the rucksack, so that there is no heavy spot. I split up my inner tent, fly, poles, and stakes to help with that.
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I don't know anything about the science. But I had an external-frame Karrimor from the 70s to 1991 (when it got nicked), and that carried very high on the back and above the shoulders. I remember it being very comfortable; but I presume the scientific thinking behind those has been superseded.
The move to carrying more weight on the hips makes some sense to me. But my instinct is that it's overkill when the shoulder straps do little except hold the pack on straight. I once worked loading sacks at a mill, and shoulders were our beasts of burden, so it's a shame to waste what they can do. Therefore my view is that for pack carrying weight should be shared between shoulders the hips, which is why I try to distribute weight evenly throughout my pack. I'd rather have a bigger rucksack than have to stick items on the outside.