After searching the internet for images of Quinn's Bar I discovered that there was almost nothing to be found in terms of images or text! Fortunately Don Travers reminded me that Quen Cultra has a photo of Quinn's in his book "Queequeg's Odyssey" as well as a good description of a wild scene there in late 1969. I remember going there and Quen's description brings it all back. It wasn't anything complex architecturally you walked in and there was a huge bar right in the middle of a barn like room, the bar actually encircled a raised platform or small stage where the orchestra and all their instruments were situated, the toilet was out back and very basic serving all sexes.... of which there seemed many different kinds.
Here is Quen's story about the place...