The script can download here :
http://o.garde.free.fr/astro/Multigraphe_eshel.plt
Au files should be in .dat format and file name like CH-31, CH-32....... CH-53.
The final document show all orders with red curve print for H Alpha, green curve print for H beta and Blue curve print for H gamma.
Here, the graphe of CH Cyg taken ten days ago.
You can adjust the size of the graphe by changing the first line
set terminal pngcairo size 1600, 1000 enhanced font 'verdana,10'
1600 is the X pixel value
1000 is the Y pixel value
I have some problem to change terminal in pdf, so for the moment only png file is available.