I am trying to pour some self leveling upto my sliding doors with which I am trying to get a level threshold. Can anybody @nod/ @Nickfromwales give me a rough idea of the depth I need to leave to ensure I am pretty near the top of the threshold without going over? I am thinking of leaving approx 25mm after I pour my self leveling to allow the adhesive(3mm notched trowel), Ditra, adhesive (10mm notched trowel)and 10mm porcelian tile. TIA