It'll be interesting to overlay the window sizes of the various Trijicon red dots. It seems like the HD and RCR have slightly taller windows than the RMR but not quite as tall as the circular SRO window.

RMHD2-C-3200002_50MOA_Reticle_w_3.25MOA_RedDot_.png

RCR1-C-3300001_RedDot_3.25MOA_.png