Looks like a production environment! 
Does the catalyzed primer self level or do you need to block it?
Yeah, as close as I'm going to get to a production line
It levels well. I block sand with 320 no-fil (white silicon carbide) paper. Sands extremely easily, exactly like lacquer primer surfacer. A 4"x5" quarter sheet will prep one body. The main advantage is once it cures there's no further shrinkage, unlike lacquer sanding sealer. Since it's made for automotive use it's ready to be top coated in hours, not days.
Initially I was concerned about using the right amount of hardener for a small amount of paint but now have it at 80 drops per 6 ounces of primer. The instructions say "use one bottle per quart". I started off marking lines on the bottle approximately quartering that (for 8 ounces). As I realized I was wasting a lot of paint I started counting the drops.
The black body was done with the 80 drops for 6 ounces. I put a LOT of primer on the body and still ended up with around a 1/2 ounce. So the next one will be 5 ounces of primer and 65 drops.
