The connection of the seat stays to the seat cluster is one of the places a builder really gets to play with the aesthetic. I build frames with both fast-back and side-tack stays and while they function the same they have much different looks to them. The fast-back have a more modern feel to me while the side-tack, like those pictured below, are much more traditional.
I construct my side-tack stay caps from scratch so that I can get the look I want as well as to save a good chunk of weight compared to the solid plug style that are so popular. With the fabricated caps the stay is hollow right up into the point compared to the plug type that are solid for a good 35 mm. The plugs work just fine but I can’t see using them when I can make my own and have them be hollow and light.
Anyway, here’s some side-tack stays on a bike I just completed for Barry. It’s on it’s way to JB today and tomorrow I start another JKS.