First off: I’ve been enjoying my Index 01! Thanks for bringing it to life. 
Maybe it’s too early, but I thought I’d share an idea for the next version of the ring: a recessed button!
One issue I keep having with 01 is accidental button presses. If the button is angled towards my thumb, it tends to activate when I’m holding something like a bottle. If the button is pointing straight up, putting hands in pockets or pushing against any object with an open hand or a fist will trigger it (am I the only one who likes to push off the couch like this? 
). If the button is angled away, it’s hard to press. In my first few days I’ve probably had as many false button presses as legitimate ones. I haven’t tried gloves yet, but I see other people are finding the button also gets pressed in that situation.
I wouldn’t mind a thicker ring if the button was inset into it, so that hard external objects couldn’t easily press it, but fleshy fingers could! I’m thinking of something like a concave indent for the button, so it’s sorta “sunk” into the main surface of the ring itself rather than poking out from it.