Hi,
There is unfortunately no standard protocol for garlic, and my article merely was a wild ramble on HOW garlic might work, and why it might not.
In any case, I administer garlic in this manner, presuming the malady to be ich (cryptocaryosis):
If the fish is no longer eating, you can forget about garlic.
If the fish is not an herbivore, then you will have to use extracts (Kyolic, etc.) to soak their accustomed food in.
If the fish IS an herbivore, you can attempt feeding raw, fresh garlic.
For raw garlic, I use morsels no larger than the fish's eye, fed from once to thrice daily.
Dosage is really is up to you, and a number of fishes can be quite aggressive in pursuit of garlic to eat, including many tangs and even some damsels. You know you are feeding wayyyy too much when you see blood-tinted mucus trailing from the anus of the fish --while alarming to see, this rarely is a fatal condition. You know you are feeding too little if you still see evidence of 'ich' on the fish.
The basic idea is to keep feeding for at least 72 days from the last visible manifestation of ich, and to make sure ALL fishes in the tank get their share. This is supposed to deny the parasites of recognizable hosts (the fishes wind up 'smelling' unfamiliar).
If even one fish in the community remains untreated, it will likely become a refuge for the parasites, from which a recurrence of the plague will spring after you're done treating all the other fishies.
I really wish there was a standard dosage available, but that will have to come from the multitude of individual experiences of reef hobbyists the world over, hehe. To wit: YOU do the dirty work!

horge