I purchased a Bur cam easy flush system. I intend to build a platform around the tank lay down a layer of plywood and tile. My question is do I mount the toilet flange to the tank and install plywood, cement backer and tile around the flange or do I lay the plywood first and install the flange over the plywood. In the directions it tells you to mount the flange to the tank and cut the plywood around the flange but it doesn't say anything about if you plan to tile.