Try using a standard Dial Gauge to get your bed nice and level.

This Mounting clips onto any standard 20mm extrusion and particularly the CR10S. Slide it along the X and move the Y back and forth to find any deviation from your ideal height. It is quick and easy to set.

Notes: Always unclip the Dial Gauge mount before printing unless you want your extruder and gauge to say hello to each other.
As you slide the Dial Gauge back and forth it is possible a mark could occur, I have used PLA and the clip has not marked my machine in any way.

Happy printing.