Labeling has been a battle for me...
I started by purchasing a Dymo label maker. I thought the labels would print an peel an look ok. Nope. The labels will work for identify the wiring bundles, but no where near the quality I want on the panel.
Next Up, Decalpro. Spent the $$ money and bought the sample pack and the laminator. Taught myself the process running lots of samples. Then I purchased more supplies to make the labels from the white foil that seemed to work best in my trials. After the supplies arrived, I spent the next couple of weeks perfecting how to get the decalpro labels to properly transfer. It takes a whole lot of practice to get the letters to transfer, and not have some small defect that causes you to redo a label. I did manage to complete my entire panel. They looked great. -- Then I had an issue with the clear coat. I used Rust-Oleum Ultra Cover. After spraying, it peeled and messed up my entire panel. YUK. So in the end, the decalpro looked great, but had huge up time for learning. I could have redone them, and found a better clear coat.
Currently, I have my panel labels out at an engraver. They are being laser etched into material that makes name plates. The material is .020 thick, and I am hoping this will work. I will post photos when I get them.