Testing - testing - Houston we have some problems

What a beast - That was the first comment from my friend who helped me setup my 20x24" camera. And it is. It looks like a beast, it handles like a beast, but I love it like only a parent can love their own kids. We wanted to test the camera, but it has no bellows yet and I dont have a lens that will cover the 20x24" format. Well we made a "bellow" with 4 rods, a black plastic sheath and some meters of fabrick made for keeping light out. After checking that it was light tight we set off to make a pinhole lensboard. It worked fine.
Loading the film is quite a work. It had not imagined that it was that much harder to load 20x24" film than 8x10 film, but trust me, it is. The filmholders have been printed on a 3D printer in a plastic material that is very hard and does not flex. It was easy to slide in the darkslide. Mounting the filmholder in the camera showed where there was a few things that needs to be fixed. The camera moved and there was a lot of flex everywhere. When we developed the film, we could see that the filmholder is not lightproof. Everything else seems to hold its own. It was fun to shoot the first sheet of film on the camera, but it makes me want to finish it ASAP.

Here are the points I need to change:
The mechanism that locks the movements should flex less. I think it is a combination of the cables and the material in the joints. Maybe I should try to use hydraulics.
Get a real bellows.
Get real ground glass.
Get a lens that will cover 20x24"
Fix the filmholders lightproofing.
Find some places to save weight without loosing any strength and rigidity.