Shooting macro with cheap focusing rail

My biggest challenge shooting macro with reverse lenses is razor-thin depth of field. The lens focusing ring doesn't work and I had to move the camera to or away from the object to nail the focus. Very tedious exercise. I started to look for some sort macro focusing rail and just got one from eBay for $11 delivered.

Rig assembled (X-Pro1 with Nikkor 28/2.8 in reverse)

How does this rail work for macro?