I have 2 ideas I'm doing/diid:
1-- I hinged the deck between the rear shock towers. I think it was where the original hinge was. That way I can lift up the deck behind the seats and store stuff (tools, air compressor, jumper cables, etc.) in the wells that are under there. I also cut a rounded shap ( on my 280Z) to fit the full-size spare tire. You might not need that on a 240.
2-- If you are going to replace the door panels, cut off the top section, maybe 2-4 inches down, where the fuzzies are and attach the new panel to that. It will make the door panel hang right, the glass won't bang on metal, and you got a nice place to rest with your elbow out the window.
Only thing is that you need to fasten the panel to the door with some kind of fasteners. Let me know if you find anything that works in place of the stock clips.