Butt plate width is only one criteria - drop at the comb and heel are also importand. If there's enough drop at the comb to have a relatviely flat comb, ie: level with the barrel, the stock drops away from your face on recoil, instead of rising up to smack it. The greater the angle of the comb to heel, the faster the rise. That is why heavy bore sized English guns have quite level, parallel combs.
Just measured the butts of my .69, 20 bore, .577 Musketoon and Kodiak .58 DR. the first 2 mentioned have 1.910" butt plates with the Musketoon slightly narrower at 1.800" and the DR runs 1.75". All of these guns fairly well follow English design and are easy to shoot with heavier than normal loads.
Even the light weight, 7 pound Musketoon, handles 110gr. to 120gr. quite easily, although it does bark loudly with it's short 24" bl. I didn't chronograph that load in it, but did measure a mere 75gr. 2F GOEX at 1,308fps, a speed that Lyman required over 110gr. to make in their book. I was pleased with the stubby gun velocity and accuracy wise with patched round ball.
My .58 Hawken at 11 pounds was not pleasant to shoot with 120gr. or over, yet it demanded 140gr. 2F to shoot accurately at 100yards. That was too much and I sold it due to it's recoil-induced pain - narrow, hooked and rounded side to side butt - a disasterous shape in a gun that kicks.