Scarcest First Issues On Document?

Looking at some of the revenue-stamped documents posted here got me thinking. There are plenty of common First Issue documentaries that are not-so-common on their original documents. But which of the types are the hardest to find on-document? I know the high-denoms would be the toughest, but I'm just talking generally -- like Playing Cards vs. Passage Ticket.

Playing Cards stamps (along with Proprietary) were not supposed to be used on documents, only on proprietary articles. All others could be used on any document after Dec 25, 1862. Before that they were only supposed to be used on the specific type they were created for. Once that happened, the various plates were used fairly indiscriminately to print whatever values were needed at a given time. That's why some stamps are very common and some much less so. The tendency was to use the same plates over and over.

Helpful observations -- thanks! So, I suppose the rarest appropriate uses (pre-12/25/1862) would be on documents that were the least often issued. What would those be?

Your question is somewhat double-edged: are you asking what types of DOCUMENTS are the most scarce or which 1st issue revenue stamps are the scarcest to find on document? And do you just mean transactional types or drilling down into imperf vs. part perf. vs. perforated vs. silk paper?

Beyond that, as Bart states, there is the distinction of matching usages during the EMU period (generally accepted to be though mid-1863).

In other words, there are many different ways to answer the question. :)

For example, a matching usage of a 1st issue PASSAGE TICKET stamp I don't believe exists. Some of the imperfs are not known on document; many others have populations in single digits.

For general DOCUMENT scarcity, an essential work is Michael Mahler's "A Catalog of United States Revenue-Stamped Documents of the Civil War Era by Type and Tax Rate." The census numbers are now out of date, but the comparative rarity ratings still apply.

I guess I was just asking about transactional types -- let's set perf vs imperf aside. Sounds like a matching stamped Passage Ticket would be the rarest, if it exists. It's a little surprising that one doesn't, given how many tickets must have been purchased. Would this be due to the fact that tickets were generally discarded once they were used?

Passage Tickets with any stamp on them are extremely scarce.