For turkey, a better benchmark or standard would be to use a turkey head and neck target. I trace around my fist and wrist set upright on the paper, it makes a good silohuette. Put the paper up at the max distance you think you'll get a shot. 40 yards is a good start.
Pick the choke and load that puts the max number of pellets in the head and neck. Shoot at least three of each and average them out.