Ive got an 870, I have a knoxx works really nice, but I decided it was too heavy/bulky. THey do work as advertised though
As for a shell holder, I hated that so for my benelli I got the ext magazine. Now I just load a days worth in the tube and off i go, no jiggling in pockets and nothing hangin off the stock. It adds some weight but Id have to carry it anyway so might as well be in the gun than on me. I can set the gun down if I need a rest LOL
but id go with some paint, or camo form tape. and a good choke, That will end up being the most expensive part anyway, unless you get lucky enought to find the right one the first time LOL
Good luck
Good luck