Dave

mitering edges of tiles is an old school method for ceramics, used before trims were made, but a handy technique on marbles etc. as there edges can be honed with a suitable smoothing block, but this cant be done with ceramics etc, as it exposes the biscuit of the tile thus when not smoothed it will leave sharp edges, tell the builder you advise against this method.. if they insist then a good tile saw is the rubi d200 wet saw, it has an adjutable tilting split bed, so ideal for out of true mitre's... good luck...dave..