So sorry to hear your vision problem will not be quickly resolved! Do you have a friend that could finish it for you? Hand quilting looks easy, and maybe for some it comes easy too, but for most it takes time and patience to get a stitch that you are happy with. As for size, look for 9 or 10 betweens, any number higher is a smaller needle that is harder to load stitches on, and much higher and the needle gets long and harder to control. I personally like the Thimble Lady thimble also, and while I have Roxanne needles, and they work fine, I find them harder to thread, so look for something w/a larger eye, especially w/your vision problem. And, make sure you have good light, that makes a big difference!
Hope things get better for you soon, and your quilt is great!