T206 520 set ?

[nineunder71]

This is very interesting.

James, PM sent regarding a couple questions on the bottom half of your Post #2.

As Sonny mentioned, my first thought is there should be at least 2 OMs (not to mention any of those super tough Print Group 1’s that have lower pop than any other back): Elberfeld portrait Wash & Cobb Green (much tougher than Sov150)

Also, I have less than 7 total Sovereign 350s for my off-back set and I think those subjects should be easy to figure out. Probably an instance like the Cobb Green.

The overall numbers there James, really look great, thanks for posting that research! As others stated, wow it would be a ton of research to start actually drilling into the exact total population of each subject’s rare backs, but it would be extremely neat to have this tallied somewhere.

Thanks for the post and look forward to seeing where this goes

Colton