I got 20 for $10 bucks (free shipping) and it takes 30 seconds to drill the hole and put them in, plus you can use them in just about any container.
I do like your brooder set up. and the hangers.
I did a pic walk through on how I did mine. If you are interested. Here is the link. Hope it helps.
https://www.backyardchickens.com/t/755291/by-request-my-chick-nipple-water-walk-through-with-pics#post_10703145