We had some questions about ideas when it comes to installing the cockpit. In my plane, I made the instrument panel fixed and the two separate tubs removable separately. For the front, I made a permanent frame within the fuselage. I slide the cockpit in at an angle and set it in the rails, then I push it forward to its position. The rear cockpit sits on a fixed cross brace I installed onto the fuselage. This brace (See pictures) holds the front and the back of the tub itself rests on another rear piece I installed into the fuselage. The tub itself has been reinforced for more rigidity. See the pictures. Last picture of the inside and the frame does not yet have the middle cross mount. This was added a little later. Hope this helps you guys with the questions!

Thanks!