I wouldn't mind deep diving into that (I'm a software engineer so that shouldn't be a problem), I just can't find any guidelines how to approach 3D panel customization. From what I was able to gather the panel just needs to provide a surface which is used to render GTN UI. I just don't have enough details how to do that.
I can't seem to get GTN750/650 to work as a part of the 3D panel in X-Plane 12 (I was trying Laminar Baron 58 and Cessna 172).
I understand that adding 3D panel to any aircraft in X-Plane 12 isn't really difficult - is there any definitive guide how to do that?