The other thing to do if you don't have blue, is to clamp a straight edge on the top of the saddle parallel to the long axis of the bed. While tramming it in, mount a dial indicator on the bed, and sweep 1 edge while traversing the saddle with the leadscrew...IN ONE DIRECTION ONLY. Once it is dead parallel, check the parallelism while moving the saddle in the other direction. Ideally, you should get the same answer....though I suspect it wont be....but ....then you will know.
Dave