One of the spools only has a top, not a base. This made the work much easier as I could test different diameters of brass tubing with it by sliding them on. The spool is shown with the original clip.
I took a piece of 9/32" brass tubing (a good fit on the spool shaft) and taped the end to the same length as the original clip.
Set calipers to the size of the gap in the original clip, then use the points to mark the brass. With a junior hacksaw cut the base of the gap at the tape end of the scratched marks.
Cut down the inside of the scratch marks to the base cut to remove the waste. It is easier to file the rough edges now with a needle file. With the hacksaw cut the end off the tube, and you have your clip.
Here's the clip in place:
It works as well as the original to hold the ribbon in place.