An interesting update to this conversation. I just read a short article with wonderful statistics on lost coin finds found at the archeological site of Venizelou METRO station in Thessalonica during the years 2008-2015. I have been using information on coin excavation finds to create a better picture of rarity of a specific coin. I normally only focus on tetartera but this article went through Roman to Byzantine times ( 4th to 15th century.).The tetartera finds were interesting to me but I know we have many more collectors of the anonymous follis. Now, granted this is only one site but they found 553 anonymous follis. This is the ratio for each type. It creates a wonderful picture of anonymous follis finds in Thessalonica and gives part of a guideline for the rarity of the individual issues.