This trunk lid has 7 coats of Universal on it with 30 min between coats. I put that much on because I wanted to be able to flatten out over the stripes. I only used trizact 1500, 3000 and 5000. Then the 3M Perfect It EX system using a Flex. No blocking nor wool. I will say its my experience that using wool after trizact will help flatten and speed up the process but with black I didn't want to risk the swirls. Also the Universal was 6 months old. I wait on the dieback which always happens eventually IMO even if its just a light fog weeks after painting.