I use a stoeger o/u as my "kill everything that moves" shotgun.
Small game - IC on top, modified on bottom.
Turkey - cheap ($20) Wal-Mart turkey choke I bought 15 years ago on top, modified on bottom.
The turkey choke I use patterns great, but it shoots 8" low and 8" left. I killed two turkeys with it last year shooting Hevi-13 3" #6s.
Last year, I was shooting #6s in the top barrel, and #4s in the bottom barrel. The idea being that the #4s through a modified choke would provide a quick follow-up shot on a wounded bird (potentially a wounded bird in flight).
Switching barrels is something I consistently do, while small game hunting (for example trying to jump a rabbit and spot a squirrel in a treetop). I have not thought about it for turkey hunting though.
Do you switch the barrels based on the set-up? For example, thick woods no shot past 25 yards = modified or field set-up shots out to 40 yards = x-full. Or, do you switch before the shot? Does the audible "click" not cause a problem with a bird in sight?