i delete the skins layer thats generated and add my own coverings - drywall, plywood, insulation, etc... since its easier to control, split on layers, and apply materials individually so the cut sheet script will apportion things correctly (lumber vs sheet goods). otherwise - push-pull to adjust the size of each.
it would be great to have a unified version for both metric and imperial as well as real covering layers for typical constructs or options to adjust - like exterior wall vs interior wall, size of drywall, insulation or not, exterior ply or not, etc... π