I don't have different bobbin holders. My machine is embroidery only. No, I don't have one of the washers. I think the Bottom Line is 60wt but my machine doesn't seem to like it. If the prewounds are 80wt, that may be the problem. I can't seem to find the weight on any of the prewounds. I haven't tried the washers but that may help too. Thanks for your help.