My personal superthrower "The Sceptre" uses a Mag host with a turbo head. The collar will fit on top of a Mag heatsink slug, and the head threads / heatsink height can be used to fine tune focus. I would recommend that type of host for anyone considering a build with a wavien collar.
The GT is another excellent candidate for a collar. The Optolife lens is close to fitting but not perfect. With today's 3d printing technology, it is just a CAD file and a 3d print job away from existing. I think a design could be developed to allow anyone to print the mounting system which mounts the Optolife lens securely in the GT at the correct height. There would need to be a bottom piece to center the lens and hold its height relative to the LED, and a top piece that is secured by the bezel and holds the top of the lens securely. An additional piece to space the collar from the LED and center it is also needed.