Thanks for having such a helpful forum. We are replacing a broken toilet with the Toto UltraMax after laying vinyl over quarter inch plywood. The flange is a bit below the flooring surface and we are trying to decide which type of seal would be easiest, safest to use, double wax, Fernco or the FluidMaster. I did read Terry's instructions for attaching the seal to the toilet rather than the floor. Since it seems they narrow the pipe a little, do the rubber seals have any affect on the flushing action of the toilet? What would you suggest we use.