He looks nice. I'd give him a 9. If he had a bit more orange on the dorsal, I'd give him a 10. Great thick healthy shape.
I'd feed him shrimp to help the oranges come out a bit more.
And if you want to be safe, use API freshwater salt. It's cheap. I don't ever remember which type of salt to use for freshwater, so I just use that. But I wouldn't use it for color. I only use it as a healer like you said before.