The distance between the front part of the fast focus eyebell adjustment ring, and the ramp for the detachable IR isn't long enough to accomodate a Merlin DSA ring.
I had (from another project) a modified plastic adapter ring with a missing segment that should have allowed the DSA to go over the ramp, but it didn't. If I 'forced it', the mount would have gone on, but the DSA wouldn't have been on square. The corners of the ramp just foul the I/D of the cage. If I were told the ramps were solid, I'd have happily filed them smaller (and lost the warranty obviously.) But having access to the scope would have been worth it. [They really are great!]
Best solution is a modified cage. I'm investigating this.