Suspending the ceiling with existing base battens

I would use the existing slatted framework and supplement it where it seems too tight to me. That it no longer looks perfectly symmetrical behind the panels would be of little importance to me. However, the function of optimal support should be ensured.

I have done something like this before and, as written above, added battens where necessary. If you enter "ms ausbau info" into the search engine, you will come to the website with the same name. I found it very helpful back then for my batten plan.