Your suggestions are good ones, but have been overtaken by events! I forked this topic in order to have a new topic about Populating components attribute options, wherein you can see that I’ve abandoned that approach because I don’t want to manually populate the option list - and can’t find a quick way to do it semi-automatically.
Additionally, I’ve also temporarily put aside my idea of publishing the angle stock (and other metal stock components) because worrying about the details was taking far too much time away from my underlying project! I AM going to use this component as a sub-component in my underlying project, but for that purpose, I can include simple A, B, and C inputs, and just restrict myself to stock sizes, without the added complexity of restricting the component itself to stock sizes.
So for the time being, and probably a long time, detail work on THIS component is on the back burner, not off, but simmering at the lowest possible setting.