I have not tried fencing in the horizontal way, yet. I might have too.
on 32" shelves there are holes about 22" back. Use front fencing there, then you can use 22" wire dividers with your new "backstop". Keeps product up front and in arms reach on that deep shelving.
Wish base decks on the outer walls also had holes for fencing at 22" and wire dividers. I hate crawling back to get deep pushed product.