did you use to determine these are not Cherry-faced?

The cherry-faced has a distinctly redder face overall, as can be seen from the photos in the cherry-faced section. Also, the cherry-faced has not so far been recorded as occurring in New York State according to BugGuide data. In addition, another photo, taken at the same time and location (and also on BugGuide) has been confirmed as ruby by Odonata Central.

Given the variability in pattern and colour in these closely related meadowhawks I'd be loath to assign an i.d. without a microscopic examination of either the male or female's genitalia (and I've done this with many specimens).

Determining range from what's reported on Bugguide is not a good idea. The data pages warn that "Range and date information may be incomplete, overinclusive, or just plain wrong" Paulson's range map for Cherry-faced covers all of NY state and if you'd checked OC (where I happen to be an editor) you would have found 102 pages of Cherry-faced records for NY state. There are only 33 pages of Ruby.

Another Sympetrum at the same location and time isn't necessarily the same species.

If you check around you will find many sources commenting on the difficulty of separating Ruby from Cherry-faced, White-faced and Saffron-winged. It's much better to have an unidentified specimen than one which is incorrectly identified.

I can't find this name listed anywhere, including Needham, Westfall and May. Is there a new name for it?

sanguineum is a European species, hence inapplicable to this North American specimen.