If you have a scale, I would shoot for about .1oz-.2oz. You just want a hint of it in there, just enough to make people wonder what it is that they're tasting. Unless you really like chamomile, then by all means up the amount a little. Off the top of my head, I don't know how much is in a tea bag by weight.
Draft 1: Lightly smoked Weizen
Draft 2: Belgian Wit
Draft 3: Rauchbier
Primary 1: German Scwarzbier
On Deck: Belgian Brown Ale, Pale Ale, Stout