If the cockpit does not need to be dynamic (other than the dradis) then why is it a 3D model? Why not just make a really good 2D image (from the 3D, don't want to waist the work) and "paste" it over the screen. Might be able to save a few FPS that way.
I have no idea how the FS engine does anything so I'm not sure if this even worth mentioning, just putting it out there.