Back when I owned a paint store, I sold HOK paint. It's very difficult to shoot. I saw very experienced painters have trouble applying it. It's very expensive and is difficult to repair if damaged. It's really for show cars when you get right down to it. For black, I would just shoot PPG DBU with 3 coats of 2021. Wait a week, block sand with 800 grit and shoot 3 more coats of 2021. Wait 48 hours and wet sand with 1500, DA with 3000 tri-zact and buff using 3m Perfectit. Will look 3 miles deep and will be real durable. Will cost about half of the cost of HOK. We do this on a regular basis. We just finished a 77 black firebird and it looks awesome. I warn you that with black, your body work better be absolutely perfect or every blemish will show. The clear acts like a magnifying glass over black. Have fun.