from what i have learned from doing homework on this subject and asking people ( i am on the market of upgrading my rem 1100 myself )
i have found that the 3.5" mag is much better suited for goose and if you use for deer hunting it is better using it for stillhunting.i think for deer alone 3"mag is alot better suited for your needs and also good for turkey.

or just buy one of each!