I was looking at older Austrian stamps, and noticed that my 2017 Scott Classic Specialized catalog does not fully break down perforation varieties for the years in question. It does for earlier 1867-80 issues, but not the later years. Sometimes it only gives one extra perforation variety, and sometimes no perforation varieties at all (just the basic catalogue number).
The 1891 issue just says "Perf. 9 to 13 1/2, also Compound." The 1899 issues says "Perf. 10 1/2 to 13 1/2, and Compound." The 1905-1907 Issue says "Perf. 12 1/2 to 13 1/2, and Compound."
I suppose some combinations on some stamps could be quite scarce, so I was wanting to know about perforation varieties that I should be on the lookout for. I was wondering if anyone had more detailed information of the perforation varieties available, and there relative scarcity/value on each stamp.
Maybe someone who has the Netto and/or Michel catalogue would be willing to share the information?