tip: pva 2 or 3 times this will stop the plaster drying quickly if the ceiling is over 30 sqm then try a 3 coat set to keep on top of it. if there is coving remember to tape it with masking tape this helps keeping the area clean.
remember your 1st coat will require around 50% more than if it was board> this is good practice to mix up the right amount and also remember not to make this mix too wet .
this is what i do
lay my 1st coat and i let it go right off . i then trowel out and using a figer of eight motion use a sponge float. i then would treat this ceiling just like i would on board a 2 coat system. if you dont let your ist coat stiffen right up you will end up moving the plaster around from your 2nd coat.
not sure if your a customer or a spread . if your a customer i would charge £10 per sqm plus pink>