Ive just got some unifinish this morning reduced to 50p a bag and am thinking of usijng it on some painted artex really shiny silk paint. Do I still need to grit before as it syas ob the bag its fine for silk paint? And if I go over unpainted textured if I PVA beforehand can I use it? Can I throw some bonding in to build it out a bit to get over the artex I went to wickes to get some one caot and they don't do it anymore so can't get hold of it .Thanks