I am going to give you the straight dope, because I just did a shoot last night with an RB mounted on this thing that I found to be the cheapest, coolest, greatest clamp do-hickey on the planet, and I have bought three of them. --- It's the Promaster systemPRO Clamper. We sell them where I work, and also the Joby gorilla stuff, as well as bogen clamp things.
The Promaster clamper is a rigid clamp with a ball head on one end and enough screw holes to connect anything to it. -- My store sells them for $39.95 but I think a lot of places do. Much better than the gorilla stuff in my opinion.
Like I said, just did an entire 3 hours without a tripod, but had that thing on the bottom of an rb with a handle out the side and a 50mm on the front --- felt like 20lbs, but 100 percent solid clamping it on stuff or resting it on the ground three point style.
