I use a 14 for piecing but when it comes to the quilting and binding (with walking foot) I was told to use a 16. My thinking is usually backwards but after my last quilt using a 16, I had to ask.
I alternated between 2 colors on my binding so every 5" when I'd hit a seam my machine would 'scream at me-kinda like the needle was hitting a solid surface. The needle would go through but not without a fight.
So, what size needle? Thanks.