I often shoot in situations where the footing for my Gitzo 1325 is very unlevel (very large boulders on a 30 degree slope). As I move the tripod from spot to spot, it takes a painful process of adjusting each of the tripod legs to get the top plate level (so I can pan and shoot flying birdies), and I'm always afraid that I'll miss some good action during this process. So, to make a short story long, I just ordered a Gitzo 1321 leveling base. I know that several of our members have this assembly, and I was wondering how this whole deal works. Does the lever that sticks out of the 1321 do the adjusting, or is it just a locking device? Do you loosen the lever and swivel the head and then re-lock it? How much adjustment is available? +/- How many degrees? How well and how quickly does this unit work? Thanks!!