Acme threads have better load-bearing properties than V threads due to
greater cross-sectional area, but it appears that your application is
more about positioning than about load. I think micrometers have
V-threads, not Acme threads.

Haven't seen your design, so this may not work. Years ago, I had to me able
to adjust a position within 0.005". We started with a micrometer, machined
off the C frame to a mount and then bonded the plunger to the device that
had to move. Cheap quick and accurate.

Karl