• getting the 3d printed XY stage sorted well enough to match the laser-cut version
• some "0.1 mm" Vbits are more equal than others
  

At 0.2 mm pitch, the remaining copper is pretty near exactly one hairsbreadth:

...and the 0.15 mm traces -- even more thin than a hair -- aren't completely obliterated. The ends anchored to the 0.2 mm traces fared better than the ends that got cut free at the last pitch shrink to 0.1 mm. Maybe <0.2mm could work for short straight links between less thin copper areas -- like sneaking a trace between fine-pitch IC pins? Counting copper and two cuts, that would get a trace through a 0.3 mm gap or maybe smaller.