I apologize for not replying earlier. I just saw your post and questions about duplex loads. I've tried duplex loads in the past but I never really saw any advantage to them. I like the theory but I've found that with the right choke/shotshell combination I get excellent patterns and more importantly, can kill turkeys at all reasonable ranges.
That 835 Tactical with the 20" barrel is a very handy gun to have in the turkey woods and I like Kick's chokes as well. You don't have to shoot #6 shot but I do find that it usually patterns better than larger sizes. To me it just "flows" better through most barrels and chokes.
I'm just not a huge fan of 3.5" shells. Again, in most of my experience, a 3" shell will perform as well and sometimes better than its big brother. It also has much less recoil and costs less. Each gun is different however and the only way to know is to try both of them.
I have a number of readers who shoot 835's, both the standard and tactical models. I wrote an article especially for 835 shooters entitled "Cleaning a Shotgun Barrel". You can read it at http://www.allaboutshooting.com
It's not rocket science but it has helped many shooters, not just 835 shooters, improve patterning and many times saved them the extra expense of buying another choke tube or trying another brand of shotshell.
Just let me know if I can help.