I have a bath remodel coming up where I'll probably tile over the existing tile. It's a solid newer high-end home with really ugly floor tile. The standard procedure is to clean it well and then sand the existing tile to help the new tile stick. Does anyone have a recommendation on sander/grits and/or experience with this? Presently I got an ETS 150/3 and a DTS 400 but would buy another sander if that made sense.