Addressing a few issues... the fermenter holding the IPA is 20 hecto-liters, but the batch is only 11 hecto-liters total. It just so happens the brewery's main fermenter is rougly twice the size of the batch. The fermenter has one opening and it's on the top... perhaps an 18-inch round opening. It has two dump valves facing opposite one another at the bottom. The tank is conical shaped. There is no filter for this particular fermenter - so I've been told. I have access to pellet hops... would they be better? I believe the brewers have some at least one mesh bag that could be used for dry hopping if I go with the leaf hops... I just don't know how many bags they have. I know one of the mesh bags holds at least 2 lbs of leaf hops. As far as weighting the bags down (assuming we follow that course of action), we'd have to tie them off at the top in order to retrieve them. Actually, they'd have to be tied off regardless, so weighting them isn't really an issue. The fermenter is about 20 feet tall with only the one opening at the top. It does have the ability to keep the beer temperature constant with two pipes running into it for hot and cold water. But as I'm new to commercial brewing, I don't know much more about the functioning of this fermenter. The fermenter has no side port... well, only big enough to pour into a hydrometer. You can't hook up a hose to this tiny, tiny little port.
Regarding the gravity... so I should wait until the beer is at it's final gravity before dry-hopping? I thought it was acceptable to add them when the fermentation was almost complete - like around 1.020. I want the hop aroma and taste to be as much as it can be.