Our guild has a permanent work room for our charity quilt assembly sessions. There are about 6 sewing machines in the room, and the bobbins are filled on a Sidewinder. What that means is that people who are new to a particular machine don't have to stop their work and figure out how to wind a bobbin on that machine. We use a beige thread for almost all of the sewing, which means that the bobbins can all be done alike.