I had planned to make a non-perpendicular wall perpendicular.
The problem is that it's the chimney breast that's not perpendicular, and I also need to have the thinnest studs possible due to lack of space.
The plan was to use the shortest screws possible to attach the studs to the wall and then use the shortest drywall screws available. The manual says drywall thickness plus 20 mm into the stud, but I won't (if possible) have 20 mm of stud remaining in the deepest part of the corner.
Anyone with good ideas to share?