Because the last mod was a bunch of scrap I've decided not to integrate low current 3mm led but to give 2 pieces of 5mm leds a try.
I've build in the two leds in the back of the cap and fixed the leds with double-faces adhesive tape.
Here's a impression with microswitch. So far there're no mechanical issues.
This is the yellow button.
Proudly presents the red version.
This is now a much more satisfying result.