I’ve a Viridian RFX45 that I bought a few years ago. I’d tried to fit it to the XP Pro back then but there were issues. To install it, I’ve to stack a plate upon a plate. Luckily, the irons will still co-witnesses through the glass (only just — I can even see the dot on the front iron sight). Oh, and I had a devil of a time finding screws to secure the Acro plate to the Fusion plate.
This particular optic is a closed emitter unit. I haven’t been using it, and it’s better than not using an optic, in my opinion. I do like the 407C’s view port size better, though.