sorry just read the last few posts, now I'm slightly confused..
once d&d to the wall and dry, i would use the fixings.
Andy, I take it you've used them before, how do you do it?
as my knowledge of PB is to have the screws just below surface to prevent trowel snagging
obviously with tiling its not quite the same as skimming
so are you able to leave the screw heads proud (as far in without breaking the paper)
and just apply your addy over the heads as normal?
As whitebeam
I use them all the time!! Whenever I dot n dab