IMHO anything that is critical eg any nav eqpt, small torch, knife of some description (you get the idea) should be as far as poss in your jacket or webbing. As you know your webbin will also have as much ammo, food and water as poss. This leaves the patrol sack for anything less important or too bulky.
Suggestions for the side pouches are spare rifle ammo as they are easy to get to and are ideally sized- someone else can get into that pouch with belt buckle on the floor.
The main compartment is good for anything bulky eg radio batts/ radio, warm kit/ goretex additional rations and water(stuff that you are less likely to need in an emergency).
The top areas can be used for anything really but whatever you put in them tends to rattle like hell if youre not careful.
Every situation is different and without knowing what that is you cannot give a defined llist. As for 'sop' it is your pack- as long as you know what goes where and your mates know where the spare ammo/ med kit are then who cares.
You could argue the finer points all night but remember that if you are separated from it you need to be able to continue- dont put your maps etc in there.
Yeah I got banned from using my Monroe but now I prefer the PLCE one. They do break easily however, the 'waterproof' bit at the top where the draw cord goes comes away with little effort and the side pouches scrape through at the base very easily.
Beats the siht out of rocket packs mind