Major , the main difference you have touched on unknowingly
NCOWS was founded in Iowa by and populated by Reenactors for the most part .
It is Member managed and is a NOT for Profit organization.
SASS was founded in Calif. by IPSC visionaries with a flair for Western guns .... Harper Creigh, AKA Judge Roy Bean, SASS #1 and
EMF's the late Boyd A. Davis, AKA General US Grant, SASS #2 . and run as a Business.
Race guns abound and modification for speed is allowed
NCOW's is not 'Stitch Nazis'.
It does however embrace the History & in both western ware & Firearms... with step farther allowing Double action revolvers made before 1898...if one so desires ..... 1898 is the cutoff date.... (cool as they are you won't see Wild Bunch 1911's )
SASS & NCOWS can co-exist ..... rather than pick at the differences, just enjoy the differences ...
AS to your Western NY question...not yet , but if you have a few like minded pards , a posse' can happen...
and LOTS of help will be given on the NCOWS Board to get you stared ...