I think any combo of shell and choke will work. People have been killing turkeys with front stuffers and in one magizine it shows a kid with a 410 and a good sized tom.
I use 12 ga 3" heavy shot in #4
Like what they did for my first turkey hunt a few years ago and will use them from now on.
Yes, they are expensive but when we screwed up with the decoy placement, I am convinced the heavier pellets were what put the tom on the ground at the really long distance.
Other than the Heavy shot I was thinking of useing up some of my old #4 or #2 Lead 3" goose loads from the 80's.
Figure a turkey is about the same size as a canadian goose.