After screwing the Durock sheets to the studs, must we apply a thin layer of thin-set on the screws to cover them and the small indentations they produce? I will apply Redguard after I mesh the seams, and wasn't sure if waterproofing the screws was recommended. Also, regarding the Durock to greenboard/drywall seams, is it okay to just use CBU mesh alkaline tape and thinset? Some recommend using multipurpose compound, but being that the seam is somewhat near a wet area, I am more inclined to just using thin-set over drywall compound/spackle. Since the drywall and greenboard is textured, I hope scraping off the texture/paint will allow the thin-set to adhere to the greenboard/drywall.