I'm thinking that it may prove more prudent to buy a lighter pair o' boots. Kangaroos come to mind.

For waterfowl, it'll be a 12 w/no more than 1.25oz of shot, thank you, and for most birds afield, pheasants excepted, a 20ga. with 25 grams or 7/8 oz. of #6's does just fine. Dogs that hunt close are a treasure for both young boys and old men.