I am getting ready to put down 1/4" hardiebacker over osb subfloor....for use between these two materials, hardie recommends a dryset mortar with ansi spec of A118.1....for the tile on top of the hardiebacker, it looks like they recommend a latex or acrylic modified thinset complying with ansi spec A118.4 (Versabond Flex falls under this spec)....since I am a complete tile newbie, any suggestions....thanks