I used to load shotguns with a thin card on top of the powder, then a wad, the shot and another thin card on top. The wad was dropped into heated crisco grease and then pulled out and allowed to cool (then the grease would re-solidify). This can be messy in a shooting pouch, but it helped to keep the fouling down to minumum when doing alot of shooting. The thin card put down first, on the powder, was mostly to keep the powder from being affected by the grease(aka poor ignition). I would sometimes skip the wad (when hunting), but the cards could sometimes get upset when being shot, so as to affect pattern, I don't think that the card could stay perfect in the bore.
Also, if you shooting a double barrel a lot or in league, you might want to take and wear something to protect your left wrist (if your right handed). I used a sock with the end cut off and a hole for my thumb. I still have spots on my wrist where material blasted it, some gas does blow back and out the nipple.
Wallynut
