Morning and WELCOME to the best group on the 'net!!! I think, mho, you are worrying about something that should show. What is quilting? Sandwiching batting between two fabrics and stitching them together. That means the stitching WILL show. When you are slip stitching the binding, if a minute amount of the stitch shows on the back or front, it adds to the quilting look. None will ever be completely invisible, nor should it me, for a good look to the product. Consistent stitches with a matching thread will help to minimize the look of the thread, though, it will blend in better!
Hope to get to know you better and I'm hoping you are enjoying your foray into the world of addiction to fabrics. :-)
Sharon