The GGX series belongs among the Mr.Color paints with a very high gloss. It is used where a surface should read as a factory lacquered finish: bonnets, covers, hulls and panels with not a single brush mark on them.
Paint like this forgives nothing, though. Every imperfection in the ground is amplified in the reflection, so preparing the surface takes longer than the spraying itself.
The sequence never changes: sand the area smooth, seal it with a primer, let it cure, and only then spray in several thin coats with full flash-off between them. The result is polished out after a few days, once the layer is genuinely hard. Further shades from the same brand, along with the thinners intended for them, are in the Gunze Mr.Color category. If you would rather build the gloss with a separate layer than with a gloss colour, the clear coats category offers that route, and the products for the final polish are in polishing compounds.