Another Suggestion for the RS-1
Even with a lighter weight DSLR and full frame fisheye, there is quite a bit of weight hanging on the upper rotator shaft of the RS-1. With frequently loosening of the vertical axis, I suspect the hole in the aluminum die casting will start to wear. This can be solved by adding a large washer, a thin 1/4-20 locknut on the threads and installing a vertical rotator knob with a hollow back... as used in the early Nodal Ninja 3s. I've improvised this and it works fine.