The front standard should slide evenly in the rails without too much play. If there is so much play in the mechanism that it is easy to set the front standard with too much accidental swing, then you should look for a way to tighten up the mechanism a bit. Maybe just partially tightening the lock levers when sliding the front standard will help.
And, you can always replicate the numbered scale on the other side of the camera. Get a long, self-adhesive label and copy by hand or print. If the scale is in centimeters, there are lots of downloadable rules in pdf format available online. Simply print one of these onto an appropriately sized label. You can likely get one without numbers so that you can mark your own later. In any case, if you have the same scale on both sides of the camera bed, aligning the front standard should be easy.
Best,
Doremus