I concurred with Der for as to go any brighter than the steel snare, then a piccolo snare line would be in order. Darker than brass or any metal, then it would be a wooden 14x5 thin snare way to go and so on.
As far as the the Gretsch line you can check out their catalog (Click Below). Your going all over the place with this and we can only help in recommendations. As for what exactly your looking for, go to the stores and try them until your ears tell you which to pick.
We can only suggest. You need to do the research and the footwork. If I where to pick one particular snare drum for you, then you would be either really grateful or really disappointed. Gretsch has 17 different metal snares. The G-4000 Metal Series also have the bronze, copper and aluminum snares.
Perhaps the Dunnett snare would be another avenue for your search.
Gretsch Snares
Good luck to you on your quest.