You are going to have to do some work here. Every gun and every hunter are a little different. You will need to get a pretty restrictive choke for your gun (a number of manufactures make specialized turkey chokes). Then you need to pattern your gun at ranges from 20-40 yards to see how it shoots with #4-#7 shot. You will also neee to try 23/4", 3" and 3.5" shells to see what works best for each shot in your gun and with the choke you choose. The choke and shot set up really depends on your gun and how you shoot it so no one on this board can tell you what will work best for you. You just need to try some different shells, loads and shot to see what produces a good pattern at various distances.

I also agree with the others that you should check out one of the videos designed for beginners such as "So You Want to be a Turkey Hunter" by Hunter Specialties. These can answere a lot of your questions about a variety of topics. I also suggest that you pare up with some one who has hunted turkeys before when you first go out because their knowledge in the field will be invaluable.

Once you have done some of that then come back with some specific questions and there are some experts here (I am not one of them) who can help you.

Goo luck!

The best thing you have going for you is that there is still plenty of time for you to prepare.