Netto Vs Michel Specialized For Austria

I am working through my Austria pre WWII and in the 1922 series Michel mentions that varities in paper, gum and printing artifacts are frequent (German they "kommen haufig vor"). I am noticing differences in paper thickness for the "Symbols of agriculture/labor/industry" series.

My question is does Netto describe any of these varieties, or just mention them like Michel? I'd like to know how much more detailed this catalog is before I pay for one. Or if there is a more detailed study of this early Republic period somewhere.

The 2014/2015 Netto Spezialkatalog does not list paper or colour
differences for these definitives.
It just notes that there are paper and colour differences.



If you collect Austria to any extent I believe it would be
worthwhile purchasing the ANK.
For instance the catalogue shows many constant plate varieties
plus there is a large BoB section.

Thanks. That is helpful, especially the scan!