Here is a list of barrels and the size, corresponding drill bit size, and number of holes for most 1100 barrels.
Please add to this list and or correct me if I have made a mistake.

Model 1100 12ga-34” Trap, .079”diameter hole, #47 drill bit, 2 hole barrel
12ga-30/28/26/22” .079” #47 2
12ga-26” Skeet .086” #44 2
12ga-26”(Compensator).086” #44 2
12ga-30”(Magnum) .073” #49 1
12ga-34” (Duck-Goose).073” #49 1
16ga-28/26” .076” #48 2
20ga-28/26/22” .076” #48 2
20ga-28” (Magnum) .076” #48 1
20ga-26” (Compensator) .086” #44 2
20ga-28/26” (Light weight).067” #51 2
20ga-28/26” (LT) .067” #51 2
20ga-26” Skeet(LT) .067” #51 2
20ga-28” Magnum (LT) .064” #52 1
20ga-28” (LW Magnum) .064” #52 1
28ga-Reg Skeet .067” #51 2
410- Reg .067” #51 1
410-Skeet .060” #53 2

Looks good so far....thanks for posting it !