One more thing. I aligned the hole with depression the tab that aligns the Digicue so the activation button lines up correctly. Then I added a dab of white enamel on the tab on the module. That way I can see from the outside when the module is lined up correctly. Makes it easy to insert. I also put a small piece of painter's tape on the battery side with enough extra to extend up one side and give me something to grab with a pair of needle nose pliers when I want to remove it. Just fold the extra over on itself so it doesn't stick to the sleeve or Digicue module. Works great.
Cheers y'all, Southern Fried
When inserting I try to stand under the light and let the reflection off of the push button guide me. I like your idea of the white marker.
I also like your idea of a pull tab. I was investigating mylar pull tabs last week, but then John Barton of JB Cases came up with the "E for eject" method (coined by Shane). It works for both rubber housing sizes, and it almost looks like I was smart enough to design it that way (I wasn't, just a happy coincidence

Please watch https://youtu.be/2Vw32fzd9EU