The Trijicon 3X Red Dot Sight Magnifier will work with the MRO mounted to the Trijicon MRO Full Co-Witness Mount. The Trijicon 3X Red Dot Sight Magnifier mount has spacers that allow the height to be adjusted to align with the MRO on a lower 1/3 co-witness mount or a full co-witness mount.
This Trijicon MRO mount is a full co-witness height, translating to 1.4" to the centerline of the optic. When using NVG's, a lower 1/3 height or higher is usually preferred. I would recommend the American Defense Manufacturing Night Vision MRO mount. This mount will provide you with a centerline of 2.33", making it much easier to use your NVG's. Keep in mind, all of this information is based off the AR15 platform. If you are using a rifle/pistol that is not an AR15/AR10, you can use lower height mounts. You can find the American Defense Manufacturing mount using the following link:
https://www.opticsplanet.com/american-defense-manufacturing-ad-mro-nv-mount-for-trijicon-mro.html
No, the PA scope uses an ACOG mount.
This mount would work for that application.
This item is for the RMO not the SRO and yes it will cowitness.
Full or Absolute co-witness means that with standard height iron sights on an AR, the sights will line up dead center in the middle of the glass. A lower 1/3 co-witness means that the optic sits higher and the same set of iron sights will line up in the lower 1/3 of the glass.