Advice? Adding new fish back into display tank

Hey guys!

I have a couple of questions. As I mentioned in another post, we have been doing a 76 day quarantine of our display tank as we had parasites that started killing off fish.

Well, after a long 2 1/2 months, we have finally started putting the fish back in the display tank. We started with the least aggressive fish. Now it is about time to start with the more aggressive ones: namely our tangs.

Prior to the qt, we had two tangs in the tank: a purple tang, and a powder brown tang. Unfortunately the powder brown tang died as a result of the parasites. So we replaced him about 2 months ago and he has been in quarantine (in a separate tank from the purple). When discussing a couple of weeks ago about the best way to re-introduce the tangs, several people had commented that it is easier to add three tangs than it is to add two (it spreads out the aggression?). So we decided to add a third tang and purchased a squaretail bristletooth tang. He arrived three days ago and is now in quarantine (in a separate tank from the other two tangs).

This brings me to my questions:

First, xroads had suggested if we were going to order from Live Aquaria that we ordered fish through the Diver's Den, since they go through a quarantine process there - so we bought the SBT from there. My question is this: since it was purchased through he Diver's Den, how long should I keep him in QT before moving him to the display tank? Since they have already QT'ed him at their location in Wisconsin, am I safe to introduce him into the tank without waiting for 3 weeks? He appears to be healthy, but wanted to know people's thoughts on this that have ordered from the Diver's Den.

My second question is if I should introduce all the tangs at the same time, or start with the least aggressive? Although I am not even really sure which one that would be. The PBT is probably the least aggressive, but not sure which is more aggressive: the PT or the SBT. The SBT is definitely appearing pretty aggressive in the QT tank (it appears as though he killed a small chromis that was in there).

I have also heard people suggest that we use an acclimation box when adding the tangs back in. Does anybody have a cheap used one they would want to sell? Or have one that I could perhaps borrow for a couple of weeks (Urbandale area)?

Thanks everybody!