My own findings:
(These descriptions are far short of being complete recipes.)
3" Shell with 1.875 Oz. of #6 Unplated Lead
#1. Remington 870, 28" Barrel, .675 Indian Creek Non-Ported Choke with No Wad Catchers
181 in 10" at 35 Yards. Clumps and open patches inside 10" Circle.
#2. Remington 870, 28" Barrel, .655 Ventilator Ported Choke
167 in 10" at 35 Yards. Very evenly covered 10" Circle.
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3" Shell with 1.875 Oz. of #4x#5x#6x#7.5 Lead Mix
#1. Browning BPS 28" INV+ Barrel, .665 Indian Creek BDS SS Choke with Wad Catchers
204 in 10" at 35 Yards, at 59 Degrees.
#2. Remington 870, 28" Barrel, .665 Indian Creek BDS Choke with Wad Catchers
141 in 10" at 35 Yards, at 59 Degrees.
#3. Remington 870, 28" Barrel, .655 Ventilator Ported Choke
186 in 10" at 35 Yards, at 56 Degrees. Very evenly covered 10" Circle.