Well, since I have enough isocyanates in my life, I didn't want to use the Clearcoat Restorer, so I tried the Gelcoat Restorer on some failed clear on my SO's car that she's getting rid of shortly. It did improve the gloss quite a bit and created some hydrophobicity, not sure if I will be able to test the longevity depending on how long she has the car.
My thinking on this was if the GCR soaks into chalked gelcoat and makes it glossy again, then maybe it will soak into basecoat and make it glossy again. Which it did, sort of. It was a little streaky, however. Sorry, no pictures (I know, I know).
My next off-label use is going to be as a tire coating, since I have a quart of this stuff and it looks just like a tire coating.