I use a roll of butchers paper that is 36" by run and as Chuck H has said. " I'd pick a load and start at 25 yards, moving back 5 yards at a time, shooting at least a few shots, until I began to see the pattern get to the point it's not reliable."
I shoot SxS's and pattern new loads at the distances that I shoot until I'm happy with the gun's patterns. For me, Imp Cyl and Mod chokes are adequate when shooting over a pointing dog. Bore size is irrelevant and depending on the bird to be hunted, I shoot 3/4 oz., 7/8 oz., 1 oz. and 1 1/8 oz. loads.
