Shades Of 6 Cent Small Queens

I have three nice 6 cent small queens, second Ottawa printing, with 3 different shades. They were reported to be the normal red brown shade, chestnut, and chocolate (43, 43i, and 43a). But I am having doubts about which is which. I have attached a picture, which will never capture the shades perfectly, but you can compare them at least side by side. I won't say how they were previously identified to try to avoid any confirmation bias, and reveal it later. Would like to hear what others think.

My go-to reference for Canadian shades is from the Meyerhof collection sold by Sparks Auctions in April 2023.
https://stampauctionnetwork.com/IK/ik4611.cfm

All these 3x examples look like they have a 'red' tint to them. My 43a has little 'red'.

I think that hundred-year-old stamps that were produced by hand mixing ink batches in differing and oft times poor lighting conditions will have different "shades/colors/hues/tones". Close enough for government work.

Mine.
They were colored by someone who has a great deal of experience and who I would consider an expert on the issue, though the scan and monitor might make them look somewhat different than you'd expect.
C.

Thanks ZebraMan ! The pictures from the Meyerhof collection are a huge help. Based on this reference, I would say that the stamp in the middle is definitely deep chestnut, the one on the right is probably chocolate, and the one on the left is either red brown or regular chestnut. For the record, the two stamps on the left were purchased as a pair described as red brown and chocolate, and the stamp on the left was obtained separately described as chestnut. When put side by side, I couldn't reconcile the shade descriptions.

dm.

There is a Canada Small Queens colour guide. See: https://goscf.com/t/55055

Found the following online regarding colour guides: