The products i use is Gtechniq, and your right you get the application wrong and its not polish it to correct it , its sand it or respray. i use C1 then EXO V3 after that you can clean your car with water nearly , as almost everything will run off the coating. of course there are chips etc on the car that i cant get out but car is 13 years old so i will make it as presentable as i can. i enjoy cleaning and driving my cars. it gives me something to do.
I used only 8 mL of C1 to coat the whole car.... paint only not the glass although you can. and i used 13mL of the exo product.
Of course i used there P1 polish to remove swirls and holograms. i hope this helps.
Good lighting is a must. if you miss removing any coating then your stuck with it for 6 years or so.
Prep prep prep. if you dont prep well you cant expect the sealant to polish a turd....
Dont rush enjoy it.
Make sure your car is completely dry! i mean no water anywhere. if a small drip runs over the uncured sealant , or when your applying it, its game over!.
Use new micro fibre cloths not old ones