Jeff- I would suggest you go with only a ball, or a shot load, not buck and ball, due to the spread of the buck shot in typical buck and ball loads being inneffective for the most part. Typically, the buck shot is on top of the ball. Since the ball's greater mass would tend to push throught the lighter 'shot' after leaving the muzzle, it would tend to scatter the buck further than if it was loaded below the ball. The might work better, however with only 3 or 4 shot along with a large ball, there would be little 'help', I'd think on a turkey. Of course, testing would show you for sure - I'd use butcher paper off a large roll - works well for patterning. for a none-choked gun- 25 to 30yards would be the distance I'd test at.
A shot load can be assisted by using a shot 'collector' cup, like a roll of paper (post-it-notes) trimmed to length. Push the 'tube' down onto a wad that has been seated 1 1/2" below the muzzle, then pour in the shot, then seat an overshot wad and push the whole shot load and wads down at the same time.
I haven't gone after turkey with my smoothbore, but do use 1oz. 7 1/2's or 8 1/2's for shooting trap, along with 2 1/2 drams of 2F GOEX - (68gr. to 70gr.) At times, I will load as heavy as 1 1/8oz. and 2 3/4 drams(75gr.) if the birds are catching wind.
Any choke in your bore?