I believe that the G2 caliper paint is brush on. With the cash that you’ve invested into your calipers, I personally would never consider brush on paint. I would lightly sand, primer (also acts as a fill agent), paint, then clear. All those products can be found specifically designed for brake calipers. Good luck!
A friend of mine has used it (custom mix in school bus yellow for his BOSS 302) and it looks damn near like powder-coat. I believe the paint has self-leveling properties. But, I did buy a Preval spray can for this job with the paint.