Guns, Dogs and Blades QnA

Waterfowl hunters: please educate me on your preferences for "non-toxic" shot shells. Looks like I'm going to have to buy some for upland wing shooting in my new state. So I like using my under/over for grouse and pheasant and have always run an extra full choke over a skeet choke. Lower barrel for those close ups and the top for reaching out and sealing the deal if I miss the first shot. I think that I hear folks say not to run steel in restrictive chokes. Also I have a 28 gauge side by side that is tough to score kills with and is limited to 2 3/4". What do ya'll think about Tungsten vs bismuth for heavier hitting power in smaller shotguns? The Tungsten folks are claiming I can kill stuff with No.7. Man I'd have a hard time buying that, at the price of Tungsten, if it doesn't deliver. Please advise and thanks in advance.