I had used ple22 which is a similar product but easier to apply than CQuartz. The rainbow effects will be diminished once the coating cured. I think if you talk to some of the professional detailers, they will tell you the environment, humidity, and temperature impact your curing result. Have you seen people put the car into a car to sort of bake the coating (the product is called Modesta)? These processes are a little too much for mine. But once it is cured, if you still see rainbow effect, you can hit it with M102 to flatten out. Rainbow effect was told an uneven surface which there are high points of the coating. Personally, I think they are last longer type of wax. But they can't protect you from bird poops. :biggrin:
Among all the coating products out there, I think the prep work is the most critical part. The clay bar process is the most important one for an older car but I always find it the hardest one to ace.
For reference, my friend just had his GT3 clear bra the whole front clip, cost was about $3000. A paint correction typically cost from $300 to $1000.
I am going to do mine this summer after I shelved my DA 3 years ago. May be I will try to document the process.