I just installed Hardibacker for a shower re-model.One wall I maybe didn't cut enough off and have a real tight fit between another piece of hardibacker and drywall.I am concerned that this might create problems later with expansion? The rest of the walls fit together easily.Right now everything is just screwed down..Also,what is the easiest way to layout walls useing 4" tile with a 2" border? Thanks in advance......