Mine's a midarm 15" Bailey. lt winds bobbins perfectly, but you do get more thread on prewounds. As for thread, it depends on the project. The polyester is finer, so it works well for fine, close quilting ( l've even used machine embroidery thread for special heirloom style projects). The cotton heavier threads show up more, so they're less suitable for quilting that's close or has a lot of backtracking. l use it for te cotton patchwork charity quilts l do.