Congratulations on your featherweight!!!!!
I like to use 12 stitches for my quilting projects. I have bought bobbins online at ebay but also at my local Joann's. I just always make sure that I have a bobbin with me to make sure that get the right size. Most of them will have that they fit the 221 or 222 right on the package.
Good luck and enjoy,
Thanks,
Sherryl
Candlequilter