I've been researching this for a while now. My primary concern is the factory rear sight dovetail and the striker safety channel cutout. If the RDS is mounted too far to the rear, the ejector side screw hole will will only be a few threads deep before it ends at the striker cutout. Too far forward and the rear dovetail won't be fully covered, leaving a gap. Completely in front of the dovetail won't work either as the screw hole would be directly above the extractor pin.
I've gotten replies from ATEI, Fire-4Effect, and Battlewerx to get mine milled for an RMR. ATEI said it's a go, Fire-4-Effect and Battlewerx are still researching.
Traditional RMR Cut:

RMR cut with indexing screw posts:

I took some basic measurements and this seems to be the only option as far as positioning the optic with the traditional method ATEI uses. An Glock iron sight forward of the optic should be possible, but I'm not sure if there's enough metal to mount it in the back. This drawing is not to scale and the P-10 in the photo is pre-production, the rear dovetail looks twice as deep on mine, but you get the idea. At least in the case of an RMR, the extractor pin will be covered bu the optic. F-4-E and Battlewerx mill indexing screw posts which might provide enough thread to move the RDS farther back. Battlewerx has agreed to let me send in my slide as a guinea pig, but won't be able to work on it until August if I choose to do so.
