Pat,
I just finished shooting HOK base coat on my Delta's wing panels. First 3 very thin coats of white, then 3 thin coats of yellow. The yellow in not 100% opaque but it's very close. Total gain was 20 grams per panel. Yellow is just hard. I miss the DuPont yellow lacquer days when 1 coat covered.
Neon orange was sprayed as trim on the stab. It's quite the color, bright and reflecting. I'm curious how it will appear at the distance of interest. Neon green was rather drab. No clear yet so things will probably change
Matt,
Sounds like you are on your way with the HOK. Yellow is hard for sure. I just shot HOK white and yellow just last week. I'm getting some pictures together for my current build. I'll post it on my painting thread.