I have ALPY 600 and Baader DADOS spectrographs (the latter with several gratings of different resolutions).  I've been trying to learn and discover compatible data processing software to generate wavelength and flux calibrated spectra.  The common free programs Vspec and ISIS are the gold standard but are difficult for a non-scientist to understand and use easily.  Demetra has versions more or less specific to particular Shelyak spectrographs... for example there is a version for the ALPY 600.  I've tried it on my data obtained with the ALPY 600 and its calibration module and it works very well.

I've attached an ALPY calibration module to my DADOS spectrograph and have been trying to find easy to use software that gives good results.  It may be that Demetra will work in this regard but it is too early to tell and I've been clouded in for weeks and unable to get new data with the DADOS.  Meanwhile, I've been working with a very intuitive program, RSpec, that is likely mostly designed for use with slitless spectrographs.  It is less automated and more manual than other spectroscopy software designed for amateur astronomical spectroscopy.  But I have decided that it can be used with low resolution slit spectrographs to obtain wavelength and flux calibrated results of stellar spectra.

It is a more manual process and I need to pre-calibrate the spectra to biases, flats and darks using pixel math in a program like Siril.  I take that result into RSpec along with my ALPY 600 calibration lamp spectra.  Rotation and slant correction features in Rspec and its data selection rectangles facilitate moving from stellar to lamp spectra while retaining set values and spectral selection rectangle positions.  It is important to  do the summation of vertical columns of data in the stellar spectrum using the same data selection rectangle position in both star and lamp spectra and anything that causes a change in one data set needs to be applied to the other prior to wavelength calibrating the stellar spectra against the lamp spectra.   Basically the same rotation and slant has to be applied to both data sets and y axis binning has to be done on the same pixel positions. Otherwise, there will be a constant uniform offset between the indicated and true wavelengths of spectral features throughout the spectral range caused by slant. 

Once you get to know your lamp spectra wavelengths very well it is not difficult to get an accurate lamp wavelength calibration and dispersion value in angstroms/pixel and these are transferrable to the star spectrum image, allowing very accurate wavelength calibration.  After that, it is a routine matter to flux calibrate via division by the instrument response curve as usual.

I have been somewhat encouraged by being able to more manually calibrate my stellar spectra to wavelength and achieve a flux calibration using RSpec.  It teaches you a bit more about the process than more fully automated programs and would appear to be a good additional resource, especially when all else fails for one reason or another.