I have now moved the heavy wall panels around to see if I find a good symetric pattern before attaching them on the walls at monday.
They can work out like this but I will also move the Fun lamps a half panel to the center and adjust the lamp and panels on the shorter wall. If I do this I will have the choice to use the complete ceiling with another 66 panels and 60 Flowerpot lamps hanging from it. The ceiling panels would be centered in the ceiling then.