In a tank that large, you shouldn't have much of a problem adding various tangs. However.. be careful not to add too many fish too fast.. this causeing a spike in the bio load and every one gets ich and dies. One caution: always be aware of the "Shapes" of the fish you are adding. Avoid two fish of the same relative shape.. an example would be.. avoid a yellow tang if you have a purple tang, becuase they have the same body shape and may fight... also, if your fish appear to be having teritorial problems.. break the rock down and restack it. This will force the fish to claim new territories, and generally get everyone to play nice.
Clamp