Bev, I'm crazy about batiks and haven't had any problems quilting them on the frame. That said, I can't imagine using a needle smaller than an 18, and I'm careful not to let the quilt get too high off the sewing machine bed.
I'm also discovering the pleasures of (shh!) poly thread. Some of the nicest newer threads are poly, but without that shiny, plastic-y look. The poly is much smoother than cotton, so less friction. And don't worry, it won't tear or hurt the cotton of the quilt.
Also, don't be afraid of the bigger holes left by the bigger needles. They close right up when you wash the quilt.
Hope this helps!