Here is how I did mine after discussing with Brett248Vista. I have the same light. I used the Magpul Illuminations Kit. It comes with a Surefire mount and a generic mount. I used the Surefure mount and found it fit better but had to use a dremmel to grind down of the the fins.
I agree I like the surefire plate a little better than the generic. I have
2 of the UWL's on two different firearms so I used both the generic
plate and I used the surefire plate and trimmed it with a sharp knife.
Both plates work, the surefire seems to lock it in place, where as with
the generic plate I can remove the switch without removing the plate.
Also note that none of the rail sections in the MOE kit have enough rail spaces for the UWL. You need a five slot
rail space.
The Generic Plate on my AR
The trimmed Surefire plate on my MKA 1919 AR Shotgun.