Congrats on the new Tri-EDC Dakine234! I saw your post and tracked the discussion to this thread.
It looks like D2000 already got you squared away. However, I want to clarify a few things about the o-rings and Tri-EDC parts in general.
1) The method of securing the silicone boot on the Tri-EDC is entirely different from that of a McGizmo. The Tri-EDC uses a threaded retention ring instead of a groove/o-ring.
2) The AS568 o-ring is the only o-ring on any of Mac's EDC series lights and it provides the seal for the head/body interface. You are free to use any material of your choosing (I prefer fluorosilicone, for example), so long as it's a AS568 -017 size o-ring (and is round, of course!). I believe the original o-rings are Buna-N duro 70, but I'd have to check to be sure. I'd recommend staying away from the o-rings in the duro 80-90 range, they are very hard.
3) I wanted people to have the option to choose the o-ring material since each has different properties with it's own pros/cons. If you don't know the difference or are uncomfortable with the terminologies, I'd suggested sticking with the original o-ring material. The material will also limit the type of lubricant you can use (e.g. no silicone lube on a silicone o-ring).
4) I'm guessing by "various heights" you meant cross-section. After choosing a material, you will be directed to the sizing page. Since the Tri-EDC o-ring is -017, you should click the -000 series link and find -017 in the list.
5) The front lens uses a flat gasket, not an o-ring. This is an important distinction and is very apparent if/when you disassemble the light. The gasket info is also included in my thread.
6) D2000 is correct, the pocket clip holes are tapped all the way through the tail shroud.
7) The replacement retention rings D2000 mentioned are a joint effort between Gonefishing and myself. There has been a lot of interest but they have not made it into production yet.
