I have a bit of trouble looking down due to the pauldron. I use leather strip with holes on each end to attach the ammo pack to the lower snap on the Pauldron. BTW, the pauldron should be orange.
The pack, along with the BFG, does tend to add to the cramping issues. I usually hold it on my left side, gripping the grip as you would a rifle under the butt, then cradle it up my are like a baby.
I put the pack on after the shoulder bells are on. To help support it, I put white velcro on the top of the square of the back plate and the top bar of the back pack. I used a kids back pack staps and 1" nylon buckle to stap the pack.
I usually troop an hour or so and cut it down to a regular TK.