An engineer would understand that there is no way to adjust a linear bearing which has at least 4 bearing channels with a single grub screw.

I know you are hoping that you have found the Holy Grail that everyone else has missed but look at the way the system you are messing with actually works and you will understand that you are simply adding side load and wear in an attempt to resolve a problem with tolerance and clearance in the set of components you have unfortunately bought.

- Nick