if you go to town with the plazzy than you will end up with a tight and shiny surface totally closed almost like glass - knightmare for painting on plus the added issue off paint adhesion the criteria years ago from the training body was to leave a matt finish meaning more porous on the surface, that information was removed some time ago (I was speaking to the assessors about this the other day) as was alot of other stuff the curriculem book has nearly halved on plastering qualification but a little bird tells me - who hates polishing skim to death, says he may request that matt finish be re-inserted to the unit for plastering so in effect the new blood will be taught not to over polish..... efectively means that you will be doing it wrong......again.
As per the standard of city and guilds plastering training body anyway