is 4 oz of dry hopping too much?

Depends on the beer. With whole hops in cold beer, I don't pick up unpleasant grassiness even after 6-8 weeks. Try it for yourself and see if it helps your IPAs stay hoppy longer. Pro tip: put the bagged hops in the keg before purging with CO2 to remove as much trapped air as you can before racking beer onto them.

I've been playing around with mixed-ferment saisons, keg conditioning on the dry hops, pulling them before putting the beer on tap. Seems to have worked well so far.

After primary fermentation slows - ideally about three to four days after pitching. You want yeast activity, but not so much that all the extracted hop aromatics are scrubbed out by escaping CO2!

 

my recommendation on how to mimic professional processes, equipment, on the homebrew scale:

ideally, you carry out primary fermentation in a pressure vessel. conical is best so you can do all processes in a single vessel (minimize transfers & oxygen). you could do smaller ~4 gallon batches to allow for krausen, use fermcap in a corny keg, but in my experience, clogging the dip tube and poppits happens too often to make it a viable solution.

realizing that primary is going to be typically done in a carboy (preferred over buckets for that big surface area), you can do closed transfers by (slowly, low psi, use plastic carboy...NOT glass), he's a decent explanation:
http://www.homebrewing.com/articles/closed-transfer-system.php
make sure receiving corny has been purged with CO2 and has bagged hops weighed down w/ some stainless something or glass marbles to make sure the bag stays submerged. slowly vent gas on corny to allow beer to flow in from carboy, leaving trub and yeast cake behind.

***as mike said, timing of transfer: just as krausen is falling so there's still some yeast activity going on for biotransformation and oxygen scrubbing. BTW, yeast matters alot here...various strains have varying ability to create the incredible flavors from precursors in certain varieties of hops.

purge headspace a few times w/ CO2, then put a few psi head pressure on your corny keg, hold at ~62-64F for 4-5 days, then drop to ~34-35 (not too cold, you want to keep those delicate hop aromatics/flavor compounds in suspension!) and force carb. day after dropping temp, push out yeast/trub that's settled out. should be ready to pour in ~3-5 days, depending on the beer, force carbonation, etc. etc.

again, to confirm what mike said, w/ this process and equipment, no need to remove the hops.

good luck everyone! JC

 

whoops, one more detail! tie up the bagged hops w/ Teflon dental floss (Glide-original, not the minty one!) to the top of the corny lid to keep the dip tube free and clear.

 

I used 5oz in my split double sunshine clone. The batch with 3oz simcoe, 1oz chinook, and 1oz cenrennial scored a full 11 points higher in competition than the 3oz citra hopped batch.

 

i'd split e'm, bag 'em, maybe with something to weigh them down (sanitized glass marbles), and throw 1/2 of them in there at day 6 for 4 days, then take them out and do the 1/2 for another four and package (keg/bottle). 4oz is not too much, but 4oz at once for a full week could potentially pull out a whole lot of vegetal flavor.... which is bad.