I'm actually in process of making a double crystal chamber for my renegade, it just happens to be a spear though so I got alot of room. I'm not incredibly tech savvy, so I'm curious to see how your crystal chamber and how you go about it come out.
I could make a cheap one buy inserting a vented coupler inbetween the neck and body, but I would need a male/female coupler and I dont know where to find one.