Yes on the 4-6 drop at 40 yards with the bottom barrel. I think its really common. I also think that it dont matter much for turkey hunting, unless your expect a 75 yard shot then i would expect to be hitting feet and maybe dirt.
Ask me how i know??
At 10 yards they touch.
When you have a six inch difference at forty with a twenty inch pattern it shouldnt be a problem. I havent patterned the bottom barrel for drop st 60, but i have killed two birds with it at 60 with my bottom barrels.
These are just my thoughts, not impling the best route to go.