In my simpit, I use a basic dual-monitor arm with VESA brackets to mount my Cougar MFDs. This is a remix of this original mount which is intended for use with a small screen behind the MFD. Since I play in VR, I wouldn't be able to see the screen anyway, so modified the design to be a simple mounting bracket with VESA hole pattern on one side and the Cougar pattern on the other. Nothing fancy but it works for me!
Edit May 8 2020: added a more solid version with locking tabs at the bottom to hold the MFD more securely in place when using only two mounting screws. This one probably would benefit from printing with supports.
The author remixed this model.