And failing.
Here is the stamp I was trying to plate.

I have noted a few rather obvious aspects of the stamp (or rather things I think I know).
Color: A deep rose
Impression: Excellent (early plate most likely).
Type: III (I think)
Other distinguishing characteristics: UR and UL triangles odd. UL triangle with many lines deeply engraved. UR triangle had a line of ink linking it to the UR diamond.
So based on the color likely printed in 1857 or later. It is on cover, but the year in the cancel remains a mystery to me. If it helps the date is December 24. I think. Here is the image of the cover.

Here is a closeup of the cancel.

Resources used: Mr. Chase's book on the matter and the plating guide from the USPCS website.
Guidance welcomed.