I think the problem most people have with Ray is they get bogged down in the "des guys over dere" and "dos idiots" etc. Yes, Ray does have a bit of regional uniqueness to his dialog, but it's more Chicago by way of Brooklyn as spoken by a Canadian. I tried to write in it once, but then started micro-managing the dialog until it sounded like a bad Sopranos episode. I finally decided that if the words were chosen correctly, the reader would hear the accent without needing to read it.

Dropping in the occasion 'cuz' or 'ya think' isn't going to pose a problem, but I find reading an entire story with what I've heard one person call "authentic voice" pretty frustrating.