Agree with Robert (seapy) that the Stackshot rail, although superficially robust, lacks sophistication and is in some respects "flimsy". The latter in particular applies to the camera platform and the awkward manner in which a camera mounts onto it. There are also play and unfortunate lateral movement in the rail during its operation.
This is why my friend here in Germany designed, builds and sells much sturdier ones with 0.3 micron repetition precision...sells those to museum etc for professional work, but also ambitious amateurs (micro mount crystals etc)
https://www.stonemaster-onlineshop.de/fotografieren/stacking/stackmaster-studio/
