Okay, finally a little progress, The screen starts to emerge. The idea from the beginning was to build The screen in 4 sections so that if it need to be moved in the future it would be a relatively simple procedure. As I thought and build, all the joints between the 4 units will become somewhat visible. So I changed my plan and finally screwed the whole structure together in one piece and fastened it to the walls and ceiling.
Also, I was thinking of making the screen 1300 mm high as the final image will be, but my friend told me to extend the HDF board down to the floor and paint the superfluous surface black instead, so the dimensions today become less important at height. So of 2″3 wood I extended the construction at the bottom by 500mm.
The diameter for me is max 3 meters. Have tried the distance with my projectors so it should go well. The goal picture was to get as close as possible to 4 meters as it gives good distance and space around the simulator but I simply do not have that space. 3 meters in diameter will do for me, should go well not optimal but good.
The screen now feels stable and so far I am very pleased. I have added PDF file with my dimensions in the Download section of the website.