Vertex-H with Double rail along X-axis

Soon after completing build of Vertex-H published here I discovered that, due to poor quality of inexpensive linear rails, the tip of the nozzle freely moves along Y-axis. The play was about 0.4mm and my solution to get rid of it is published here. I have to admit – this was quick fix; I tried to keep as many existing parts as possible. Clamp add-ons are mounted with M3 screws. Initially I tried to mount them with 25mm screws but then ended up using M3x50mm screws that went all the way through o