I contacted LaRue and they recommended the LT104 mount. However, it requires a tube space of 4.9" min. The Photon XT has 4.65" of tube - it won't fit. I measures my LT111, and it also requires 4.9" of tube space to mount.
The Burris PEPR requires 4.15" - it's in the lead.
Thanks for the responses!