Seeking Information On US 1-St Issue Revenue R41 (20c Foreign Exchange) Double Transfers

I'm starting to make my way through mountains of unprocessed revenue material that I've acquired over the last several years, and one of the first items is a double transfer on Scott R41c, 20-cent Foreign Exchange (sadly the very last item I ever purchased from the late Stanley Piller, on Saturday November 20, 2021, a mere two days before his passing... R.I.P. Stanley).

Double transfers on R41c and R41d are extremely scarce, due partly to the fact that even the base stamp is not that common, cataloguing $80. However, there may be an additional reason...

I've managed to acquire 3 different examples on R41c and one on R41d, with varying levels of double transfer. As I was looking at the new acquisition, comparing it to the previous examples, what struck me was the seemingly very narrow window of time that these double transfers appear to occur in. The earliest cancel date across the 4 examples is September 27, 1871. However, given my small sample size it's dangerous to draw any definitive conclusions.

I'd be interested in knowing of any other examples others might have, and in particular, the cancel dates of the stamps.

I am unaware of anyone having attempted to plate R41, given the relative scarcity of the base stamp, the sheer number required to plate the issue, and the comparative lack of multiples extant.

Thanks.

My DT examples:

Earliest date on shifted R41 is 9/29/1871. Proof sheet is late state and shows shifts similar to the first one you listed on positions 38, 57, 58 as well as many less dramatic shifts.

I do have a pair of R41c dated Feb 2(?) 1865. But not a DT

Dan, Adding a recent copy I found. I cannot figure out month.

Oct

Very nice Robert, Double transfer at lower left. Check the back under magnification for blue silk threads, as the cancel date and this particular ink shade make a silk paper plausible (although the paper shade looks a bit dark, but that could be the scanner/camera).

And I concur with John on Octber as the month.

I have checked, unfortunately, it is not a silk variety. October looks good, hard to decipher the old writing sometimes.

Sorry Dan, my copy has a red Oct 11 1864 CDS, and no DT.