Those guns sound great BR, I wouldn't be disappointed with any of them. The 26" barrels would be great on Bobwhites here. The 28" you mentioned (including the differentiated chokes) would be the most common here as well, being an all around bird and small game compromise. The longer ones (30" or longer) would be great here for Morning Doves, Geese, and high flying Ducks.
I too have a shotgun passed down from granddad. As you said, it's ill fitting now, though it was fantastic when I was teen learning to shoot.