Hi, unfortunately not as easy as it first seems.Plastikote do an excellent "flouro- yellow" which is a very close match,but all flouro paints require a white base coat to work as they are very translucent, so looking at 3 or 4 coats .The biggest problem you are going to have is that this coulor fades very badly and your new paint will stand out like a "sore thumb".
I also have the same brakes and tried to touch up without success ,the only way really is a full repaint,which I have not bothered to do
. If you do go down this root you will need to use an acid etch primer ,plastikote aluminuim primer is also excellent...
brilliant brakes ,,saved me a few times without doubt the best rim brakes ever, so much "feel".
Older yes,,Wiser Yes, delusional Ditto.