I have a question about backerboard installation. I want to have a bullnose extend past the edge of the tub so I need backboard down the edge, correct? I am using Hardieboard. How should I install the hardieboard around the lip of the tub and down the side to the floor? Should I install one sheet to the edge of the wall that rests on the tub lip and then install a small piece to fill down to the floor?

Also, I was told to extend the hardie to the face of the green board and then just tape and mud that seam. Is this correct?