if you have a 1/16 gap, i would use a trowel to apply the glue on the
drywall with notches 1/16 less deep than the trowel you used on the cement
board so the glue surface is the same, and put the top layer of tile so it
overlaps the drywall. bead of caulk to seal the top edge when done.

randy

wrote in message
oups.com...
The sheetrock is thicker, by just over 1/16". That extra thickness my
be the result of several layers of paint over the last 46 years!