If lead is legal that is what I would shoot, the best nickle plated magnum shot I could find in size 7 and 5. Or do what K22 suggested.

I have only shot the turkey duplex loads inside of 60 yards so far. Some duplex combinations can sort of start bumping into each other especially with different densities and sizes. It is also a question of my ability but 50 yards is a long shot for me on pheasant. Pass shooting geese due to the larger target and straighter flight I can extend that some.

With the smaller size shot you can cut the pay load and save that way. You gain economy and velocity.

Even on turkey the advantages of a duplex load are a trade off. With the extra dense loads I would rather have more pellet count. The only exception is if they are mostly close shots and it is tearing up the birds too much. When the hunting is good I like to pass on long or questionable shots and extend the length of the hunt. If they are flushing crazy long I usually look elsewhere rather than take chances wounding birds.

Also if with out dogs it gets difficult to find the birds at extended ranges.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli