Now I am mostly finished with the painting and have found that with decent paint (StoColor Rapid, coverage class 1) a single coat on new smooth fleece can already look good - it certainly depends on other conditions, e.g. quality of the fleece, whether the plaster is primed or not... I applied generously and used about 7L of paint (undiluted) for a room of about 18m² (walls and ceilings). If I look closely, I find spots where the coverage is not yet 100%. But to be fair, these are really only isolated spots and you have to be very close to see them - for many probably not a problem, especially in bedrooms or children's rooms, where the walls might need a new coat after some time anyway. But now that everything is nicely masked off, neither floors nor doors are installed, I will push through and do the second coat - this time without ceilings (as I said, the small details can only be seen up close) and I won’t apply it as thickly and will spread the paint over a larger area. This has the advantage with smooth fleece that in the end less roller texture is visible in the paint, and it goes faster.