Ken,
I worked out the IR based on the A3v spectra, and then applied it to delta scorpii. My issue might be that the IR curve covers from 3100 out to nearly 10000 A. I'll try it over a smaller range and see what sort of curve comes out.
Your comment about normalising to the continuum is an acion in Vspec that I've had trouble with over the years.
thanks for your comments, Ken.
Mark