Pedro,
what you have done so far looks excellent - this is going to be one well used Defiant! Your question touches one of my pet peeves, so appologies if my thoughts on that are more than you wanted to know 😀
It is a common misconception that gloss coats darken a color. What they actually do is make the paint - well, glossy (who would have thought...) A glossy surface reflects the light in a different way than does a flat surface. Simply put, if light falls on a glossy surface, it gets reflected in one direction, whereas with a fat surface it gets diffused. This is why glossy objects tend to show very bright spots where your eye "stands in the way" of the reflections and dark areas where it does not, while flat objects look more evenly illuminated.
So if you gloss coat your model it won't get darker, it is merely the reflectivity of the surface that changes. And the same goes of course in the opposite direction - if you put a flat coat on, the surface does not really get lighter, but it will diffuse incoming light, making it appear more uniformly lit.
In short: Don't worry about your Defiant getting too dark after gloss coating it, just make sure to apply a flat coat later on to bring it back to your desired look.
Hope that helps!
Cheers,
Boris
