I've seen uvc damage on reptiles, i wouldn't call it immediately obvious to most people. Ocular damage is first to come.

I am not worried about shifting spectrum, I was worried about low priced LED "UVB" bulbs, and the fact that mislabeled bulbs have been coming in for the last 2 years (see all the "UVC" bulbs imported in for covid that ... were not). I was interested in moving to LED UVB bulbs now that the prices on UV producing diodes have come down substantially, but I wanted to verify them before I put my collection under a new bulb type.

"Homemade" as in I made it at home, or home made as in not professionally made? The answer differs depending on your meaning. Building custom niche equipment and software is what i do professionally.

If one is simply worried about if a light outputs uvc or not, i'd use these https://www.amazon.com/gp/product/B08CZ43RCP