I added two or more at a time and did not allow them to establish territory. All of the tangs were pretty close to the same size. I am sure most of you know Tangs are territorial. I made lots of caves and hiding spaces for them to hide and sleep. They bickered a little bit but eventually got along. Again, like someone said they have their own personalities.
If I were going repeat this process with my IAP ninety gallon tank, I have a very aggressive Hipo tang 3-4 inches long. He previously fought with a powder blue tang the same size and almost killed it. So there is a flag to me. If I did get a powder blue he would have to be twice the size of hipo, and I would also have to add another tang to distract Hipo tang at same time. That distraction would have to be something equal to powder blue. My thoughts and hope would be that the Hipo would tire from chasing other tangs. Its a gamble that sometimes works. The more tangs you have the more competive they are for food, If your filtration can handle the bioload its awesome. You have five lawnmowers competing for food.