How Well?
These seem to be working very well. They do have a little give if something brushes them backwards. Scraped mine the first day out. Had them about 1 1/2 " too low. Removed them and shortened them, then reinstalled. Working great now.
Mass production could be an option. I would have to check my materials pricing, labor involved, and potential shipping costs.
When it's something for my own vehicle, it usually doesn't matter how high or low the cost or labor, as long as it works the way I intended.