Wouldn't "uaine" be better? I was under the impression that "glas" refers to living green things like grass and trees.
'uaine' is more of a bright, vivid green, like you'd find in paints and dyes. 'glas' is for less vivid, more natural shades, stretching into greys and blues.
Do you know of any Irish color charts online?
Not off the top of my head, I'm afraid.