Goose hunting - 10 or 12 gauge bore

Honestly, I would avoid sky busting at all costs. It only results in wounded birds and busting up the flock of bird.   I know the temptation is strong, but a good decoy spread, good calling which in itself is an art and patience will result in better results. Whichever gun you decide on, shoot it, become proficient with it, find which choke and shell combo work best out of the gun. I do a lot of waterfowl hunting, for me it's a 12 gauge, I used to shoot 3.5  in.mags but quickly got tired of the recoil and expense of the shells, 3 in mags work well for me and get the job done.  Good luck in your search