It was in one of his old reef notes. I have the published books of reef notes, buy have to find them.
Julian does write for
www.advancedaquarist.com and does sometimes respond to questions in the forums.
The percs should host in any coral that provides protection. Once your tank is mature and can support mandarins, perhaps you could add a pair. Its important to make sure you have a female & male, as two males will kill each other.
Try find healthy mandarins, if possible like mine, some that are eating frozen brine. They can also be fed live brine shrimp.
I must add, I dont advocate mandarins being kept by inexperienced aquarists. They are hard fish to keep, but if a tank is set up proper and large enough, {as you are interested in}, they can be kept. Its unfortunate, but to many are sold to new aquarists, as cute little fish that are easy to keep in a small tank.