Well...
I have successfully used it on 2 vehicles, both on dark black (5 coats on rear lights) and on light grey (1 coat on front lights) with very good results compared to another brand's product.

Since I couldn't find it immediately in my city for my third vehicle, I bought the lens TInt from HB.
It has one major advantage and one major disadvantage compared to the other product.
The advantage, first of all, is that when you achieve the desired shade with the lens, even though it shines impressively, you can then apply a clear coat on top to cover any small imperfections or even enhance durability and hardness if desired, and then polish it if needed.
However, the disadvantage is also very significant, as it is very thin and "tears" very easily.
You have to apply 1 or even 2 coats very lightly, like a mist, and then gradually a bit more wet.
No comparison to the other product, which despite many saying it runs, I didn't encounter any problems.

So if you manage, with enough trial and error, to find where it doesn't "tear," it is very good considering you can apply a clear coat on top if desired.
While with the other product, you can't, as it immediately erodes...
It also has a quite strong smell and takes a bit longer to dry, 15 minutes for the first coat, 30 minutes for the second, 40 minutes for the third, depending on the weather of course.
4 stars because it runs a lot and you need professional skills to apply it.

Tips:
1. You can use a general-purpose thinner and a cloth to carefully remove the tears locally, and then cover them in the next coat.
2. If the lights are easily removable, it's better to remove them and spray on a horizontal surface.

Update:
After a quick 4-day crash course, I changed the rating to 5 stars as once you learn how to use this specific product, it's very easy!

In short, clean the lights well, shake for 2 minutes, and apply a quick Light coat from left to right.
After 15 minutes, apply a Light coat up and down.
Repeat again...
In 4-6 coats, you'll be good to go!
Don't worry at all about glossiness, orange peel, etc. Only Light coats!
After 30 minutes, apply a clear coat. I tried the HB 4K again.
1 Light coat and 2 more after 10 minutes, wet (without any matte, pores, orange peel, etc.)
Result... Excellent... Factory-like
I will upload photos soon...
After 1 week, if needed, you can polish with 1000, 2000, 3000 water sandpaper and then compounds.
But if you find it, it won't be necessary...
20 cm distance, steady hand, and steady tempo. (watch some 4K Clear coat videos)