Most certainly none of the above. Crystal and Saphir are way too sharp to get a good result. They are meant for the toughest of jobs. Plaster, on the other hand, is a very soft material. You want a more gentle abrasive to handle that.
I have found Granat works best on plaster walls, mainly because it doesn't clog as fast as other types of abrasives. I never go lower than grit 80 on the roughest of patches, but mostly use 120. If you can't get Granat, Brilliant also does fine but it will clog quite a bit faster so you'll use up more sheets.
