I must admit I just take em out and re fit later... but, if i come up against something i can't remove i use the paper method. ..
This works tho.,,,,, dry lay all your 'complete' tiles upto the pan, pedastal, door frame, bath, dog etc
now, imagine your'e in front of the wc, ... place the tiles to be cut on top of the tiles around the wc . Now , think of a 'school compass' you know the one with a pencil in the end, get the largest one you can find or make one with some dowelling and a wing nut & bolt and a china marker.
Transfer the measurement of the
tile (150x150) etc so the end of the compass is 150mm away from the marker...place the non marking end against the wc and the marker on the
tile...make sure you keep it straight to the
tile..scribe away & cut them off....