As you seem to be a novice at ceiling work , this is a fairly large area . Unless you can practice on a small ceiling i would forget it . I tend to use stilts for ceiling work where practical. Are u Plastering over artex?
Would not let her train on my walls ,as does not even know the basics. Better off training on wall in your own house or length of plasterboard before wrecking someones house me thinks. :lol: