I personally don't use a 100yd zero as the 50yd zero with another cross around 212 (varies by ammo/rifle type) makes more sense for me and my uses. Of course that's a whole other discussion. Anyway, I like to use these targets provided by another member here. They are both 50yd (with one designed for when a 25yrd range is all that's available) with variants for both 4moa and 2moa dots.
They seem to work well for me and you might be able to find something similar (or modify these) for your 100yd zero
https://www.m4carbine.net/showthread.php?t=75940