I really like the duplex - they pattern awesome for me. You're right on when you say that the #4's do the heavy damage and the #6's fill the holes. You never know whether that shot's gonna be 10 yards or 40 yards. A duplex gives you some extra comfort knowing that you can put some heavy lead on your target.

I would highly recommend them. This year I couldn't find any, so I resorted to Win 3.5" #6 heavy shot knockoff. They worked well. I cranked my gobbler out at 40-45 yards, and he was peppered pretty good.