Identifying 1920's Coil Stamps.

I'm having a hard time identifying these stamps via Scott's catalog. The other catalog was much easier but didn't have as many options. I list most of these and want to try to be accurate but there are so many. The differences they are calling out I can't even pick up on. Is there an easier way to identify these coil stamps? I have a few and don't want to get it wrong. Sorry for all the questions.

There is only one option for this one.
Scott 606.

Does your Scott catalog have the definitive identifier in the front? (They took that out for a couple years) That's where I'd start on identifying these stamps. . .That design is a 4th bureau design that only has a handful of associated catalog numbers. 606 is the only vertical coil. But for other issues, you can quickly narrow things down by checking the perforation gauge and watermark. Identifying types and printing method is trickier.

I guess I might just be having a hard time navigating Scott. It's overwhelming compared to the other catalog I was using. I appreciate it! Thank you!

So two different colors or just different shades?

Probably just a color shade. There is a 606a Carmine Lake listed for $160 a pair, but more likely this is just a dark carmine or deep carmine shade of the normal 40-cent listing. Here is an article from Linn's discussing the difficulty with the color shades of this same issue.

https://www.linns.com/news/us-stamp...ictory-issue