I have a set of williams fire sites mounted on a 28" remington 12 gauge. I have the rear site beyond the max. elevation marks located on the side of it. My question is should I move the rear site rearward so that I could bring the rear site back down? The ventalated rib is at its hightest point nearest the chamber end off the barrel. I believe I could bring it back another 5" to 7". Many thanks, cluck