Okay height difference between ceiling joists?

[C.Lundin]

If the primary profiles are at the right level, I wouldn't consider it a major job to shim at the other attachment points. I definitely think you should put some care into it, it will be easier and better for you in the end.

 

[useless]

Yes, there are already studs. Then it doesn't really matter how straight the layer above is, you just need to shim between with appropriate spacers at the beam fastenings so that they are straight in relation to each other.
Or have I missed something?

 

[joakim_j]

In that situation, I would also have put some effort into tucking in masonite pieces or the equivalent so that it becomes as straight as possible. A typical case where it's worth investing in the preparatory work, making everything much easier afterwards.

 

[Trattkantarell]

Yes, there are already beams. Then it doesn't matter much how straight the layer above is, you just need to shim between with suitable pieces at the beam's attachments so they become straight in relation to each other.
Or did I miss something?

Yes, that's what I was thinking it will be a bit of a puzzle to get it straight, but it feels prioritized. Thanks for the answer