tevo tarantula roller guides not snug enough

I am putting my tarantula together.  (first printer)  The roller guides have these eccentric nuts that you turn to move the roller in and out to adjust it.  I am afraid they are not getting close enough,  I can still take the part (carriage guide as an example) and wiggle it around quite a bit. 

Maybe its ok for it to not be rock solid un-wiggable.  I don't know.  But if not, is there a way to tighten things up a bit ?