RE: Do you switch chokes?
Its all situation dependant.
Because I hunt swamps and tidal timber a lot, my set ups will depend entirely on the wind. Lots of these tidal marsh creeks are fairly tight, and sometimes it can be 30 yards from the woodline to the water where the decoys will be placed. In other situations, it might only be 15 and somestimes we will use layout blinds and have the ducks almost light on top of us. I always have a Skeet, IC and Mod with me in the blind bag. About 65% of my wingshooting is done with an IC.
The only time I really change out is when I am a guest somewhere. There are times when I'll be diver hunting on the sound or bay and we will have shots at passing divers that are routinely 40-50 yards, and its very difficult to judge distance over open water. Thats when the Mod comes out. If we have a goose set up where the geese are decoying a bit out in the spread, then thats where the mod shines as well.
I use the Skeet mostly for super tight duck spots and dove hunting over decoys.