This has been asked before elsewhere but all the answers seem a bit of a bodge. i am fitting a bath 90mm too short for the space its going into. I'm looking at boxing out and tiling the gap but i want to do it properly so that water drains into the bath, even after some movement. Horizontal tiles flush with the bath lip don't seem a good idea to me: i think they need to overlap the lip. What would a professional tiler do in this situation??