Ryan, Gamecock is a easy to grow variaty. You can actually grow it in any of the conditions above. They do like moisture but will grow in plain dirt not even in water at all. One thing that I will note is that gamecock does not seem to grow as some other variaties. I've planted them in several locations and they always reproduce at about half the rate as yellow and light purple variaties. But the show they put on is well worth the effort, The flowers seem to last longer, and more per plant than the other two variaties I spoke of.
Glad I spotted this thread... I just got a pot full of black gamecock last weekend, and spent today trying to tease apart bundles of bulbs. I noticed it seems like a much smaller plant than my other irises, but I've been setting them in between the rocks around the edges of the pond, where their roots are directly in the water. Not sure if they will still bloom this year (some irises are temperamental about that), but by next year they'll be fully established. Can't wait to see the show!