Thanks for the links.!
One problem is that scikit-rf wants S11 files for ideal SOL
but I did not find how scikit-rf can generate S11 from e.g. delay, R, L, C values.
Since I have SDR-Kits BNC cal kit,
perhaps S11 for those can be generated using VNWA software,
but scikit-rf also seemingly does no interpolation;
raw measurement frequencies must match ideal S11,
so that will be another challenge.
Oristo