Just something to think about... There is no more than 1/8" between the top of a soundboard and the bottom of the call surface. If you try to stuff a bunch of momentos in that 1/8" of space, you're going to change the sound of the call, and likely not for the better. Since there are 4 subspecies, that would mean 4 photos. Given that the soundboard in my calls is 2 7/8" across, when that is cut into a pie shape with 4 pieces, those photos aren't going to show much detail. When you condition any part of the surface glass, you will then visually obscure some part of one or more of the photos under the surface.
Just my 2 cents worth, but I think those kinds of things could be better displayed in some type of shadow box display or something.
You need to decide if the call is going to be a decoration for the shelf (in the downstairs man-cave
) OR is it going to be carried to hunt with?
Knowing your preference for anodized aluminum, I'm guessing that would be your choice if you are going to hunt with the call...
An idea that came to my mind was having the 4 subspecies listed clockwise (12,3,6,9 o'clock positions) in the order they were taken, and including city state underneath...
Eastern
Topeka, KS
... and so on.
In the center of the call,
Single Season
Grand Slam
...maybe a picture of the nock and fletchings portion of an arrow between the words... maybe a row of turkey tracks around the outer contoured perimeter of the call...
Just remember that the soundholes on the call take up some space too.