TC that sounds like a pretty tight pattern. A 10 inch circle just is not that big and that's a lot of holes! Forty yards to boot. I doubt that my pet #5 load would do as well.
I shoot 30 and use a std sheet of typing paper for target.
I use #5 these days after the Rifleman ran an article about turkey loads and pellet weights/energy. Truth is, shoot your birds at a reasonable range and #5 v. #6 will not make a hoot of difference. Fooling w/ shells and chokes does give a bit of knowledge and confidence though.
Best pellet count load I ever tested and hunted with was the Activ, 3" 2-1/4 oz of shot #6. It would put 220 pellets on a sheet of paper at 30 yds. I still have a partial box, a guy at work wants them bad.
Best load I ever counted, but have never killed a bird w/, is the discontinued Federal Heavyweight, 3" , 2 oz of ..#7-1/2!!!!! It put 300 + pellets (310 by count) on a sheet of paper at 30 yds. But #7-1/2 seemed very small for a general purpose turkey load. I still keep one in my vest for controlled ambush setup type hunts where I know I won't shoot past 30 yds. (blind hunts).
Finally, isn't it interesting that we have not heard from any of the space metal, tung shot folks yet???????