Well, I added my second (and last) Tang to my system today. I got a nice 4 inch Kole Tang in seemingly excellent health.
I dripped him for 3 hours, then, at 20 minutes before lights out, I added a bunch of food to distractthe other fish, and dropped him in the other side of the tank.
Of course, as soon as the food was gone, the Mimic noticed the new guy and they spent the next 10 minutes tail splapping and taking turns chasing each other around....
The Kole is about 3/4 inch larger than the Mimic, and by lights out it appeared that the new Tang was holding his own and was not taking any more flack from the Mimic, so I have good feelings that they will settle in and co-exist peacefully. I'm not about to tempt fate again, however. Two Tangs is good. I'm not gonna press my luck.
I'll post some pics of the new guy tomorrow