Welcome to the board, Steve.

There may be near-concensus that TM is better than bismuth where lethality on ducks is concerned, and you may use it as much as you can afford with those chokes.

If you haven't already, you may also want to have a gunsmith take a good look at the gun. Are the barrels twist, damascus or fluid steel? The Parker 16 0 frame with those chokes is good for upland birds and ducks over decoys to 35 yards.