Good Day Gents! I am a carpenter who sometimes lays tile. I've done a number of jobs that i was happy with(as was the client). I have one coming up that involves 18" floor tile,and iwas going to use the fiber rock backer board as well. I know that i should probably back butter the tiles. But any other help would be awesome. I have also seen some guys put backer down dry and some thinset it down,..any preference? And should i use a notched trowel bigger than 1/4x1/4?