C7 is crap.
C5 is the bare minimum I'd use and from some of the offering I have seen lately with nuts that rattle up and down, my sissor jack on the truck is better made <g>

The OP wanted 0.1mm tolerance that's 4 thou and given his sketch with a 800 mm travel it looks like the fence is around 1M, so with a screw either end to keep this tolerance you have a max of plus or minus 2 thou to play with over 1M or 39" [ excuse mixed measurements ]

If these tolerances are 'needed' as opposed to 'I'd like' then you have to poppy up or someone is chasing errors when it's not needed.