Hello I am currently tiling a marble entry It is slopped which is finished but now the curb needs to be tiled. This is on an angle that leads up to the elevators and I would like to know how do I find my cut sense the joints need to be straight up and down as apposed to on an angle. It is hard to explain but being the guy on the crew with the least experience I would like to be able to go in with some peace of mind. Thank you!