If you are 6"3" tall, you need a longer stock. LOP should be something like 14 inches min. and that only if there is sufficient drop. With a charge not exceeding 80 grains, the recoil should be manageable. Are you shooting FFg powder? Again, FFFg powder burns much faster, and will give added recoil effect, for no real gain in veolocity, or in cleanliness in the barrel. I shoot a CVA shotgun in 12 ga. that is lighter than yours, but has the butt lengthened with a hard recoil pad( I didn't need the cushion, just the length to the stock). The length of pull on that double barrel shotgun is 14 inches. D at comb is only 1 7/8 and at heel, 2 1/4. On my fowler, the LOP is 13 12/: Drop at comb is 2 12", and Drop at heel is 3 1/4" . the fowler fits me bettern, but then, it was made for me.
I hope you have a better idea of where you need to go with that shotgun to have it fit you better. I know by lengthening that stock, it will kick you less.