A friend of mine is cutting the bearing slide assemblies for me and there are no hole dimensions in the PDF. From the downloaded Edrawing I'm showing 0.344" for the X-axis bearing slides that use the 5/16" bolts. That gives a fair amount of slop considering the bolt is about 0.304".
Is that desirable in order to align the machine on the rails? That is the only reason I can think of for that amount of wiggle.