Ok, so i finally got out in the shop for my winter project-building 2 carriage doors for my shop to replace my old 1938 overhead garage door. i got the idea for the sandwich design from an older issue of FHB but the article didn’t go into much detail about a lot of things, including the window mullion details, i figured out the actual mullions, but what is the best way to build the trim to captivate the window panes. it seems like on both of our existing house entry doors, the the outer window pane stops are slanted somewhat to shed water & are the removable pieces if the glass needs to be removed. why would these removable pieces face the exterior any ways? any feedback on designing the design of these components would be appreciated. i attached a pix of the door article. thanks again in advance.