Hi Andy – I think less than 60 files (20 or so if restricted to A or B stars). I am putting them in text files in the ISIS .dat format ( wavelength flux) so far the are all under 9,800 KB the names are as in the CALSPEC catalogue https://www.stsci.edu/hst/instrumentation/reference-data-for-calibration-and-tools/astronomical-catalogs/calspec .
I could put them in fits format but I am not sure (need to test) if that would require me to resample them to a fixed wavelength interval and I would rather not change the data.
Regards Andrew