I have been asked this question many times over the years, but only am reasonably confident of my answer in the past 5 years or so. After analyzing the data of about 16,000 entries for the McSARR (McAlvanah SA Rarity Rating), there were several candidates from the known 214 makers. Please note I did not consider examples as the Early SA Rohms by Eickhorn and Pack or variations as the double oval Eickhorn, only the Makers. My opinion for rarest would be ARTUR MELCHER. This involves only the Early SAs. Thank you, Mike
SWAG is used to describe an estimate derived from a combination of factors including past experience, general impressions, and heuristic or approximate calculations rather than an exhaustive search, proof, or rigorous calculation.