I have been trying to find some of the thicker clear O-rings in 40A-50A hardness but have had no luck, the non-clear ones are great but cover the LED of the switch. I can't double up the small ones as previously thought because they reduce travel distance to right at the actuation point, which means sometimes on a light press they key will not activate. Looking into clear dental bands at the moment but can't seem to find dimensions for their sizes.
Those massdrop rings are mislabed, there's no way they have a thickness of 0.4mm, they just don't make them that thin. Also, after reading the comments of stuff on massdrop I would rather spend the extra $5 to be assured to get the product I want and not have to deal with their 1-3 month turn-around times. For products that don't have options they seem great but, based off the customer's comments, when it comes to choosing colors, sizes, and accessories they seem to get it wrong every time.