FWIW…If anyone is still looking at this.
I went through this whole thing a couple of years back. Incessant stutter. Playing thru Bluesound Node - So why is this happening?
After a ton of tinkering, and with a lot of community help, I concluded it was a problem with where Bluesound and wifi meet. The fix was to get a RaspberryPI and use that as the wifi interface for the Node.