sandhills
I've done a bit of mallard hunting, but my waterfowl experience is slim. I only saw my first sandhills just a year or so ago. Dang things are enourmous. Their protected here in AL BTW.
"Skybusting" is largely frowned upon in general I should think. Birds are either in range, or they are not. You don't say what distance you're shooting. I can say that steel is notorious for running out of punch at longer shotgun ranges, much more so than lead or space shot, as you likely know already. BTW, are you sure buckshot is a legal load. Using "blue whistlers" was also a big no-no back in the day? You will know more about TX law than I do.
I notice that TX does allow sandhill hunting, and certain areas do allow lead for them, but federal areas may have their own spec regs, they ususally do. Were I to try sandhills, I would take a hard look at "T" hevi-shot . "T" is some times listed as "T-buck" so the legality issue comes up again, maybe I guess.
Anyhow, Such loads are sold under the moniker "Dead Coyote" for one source. I hear they are indeed great table fare.