We did the same thing. We used two denso window motors with a gear reduction system for the first joint. Then we used an eight inch stroke piston for the second joint and a six inch stroke piston for the claw. As you can kind of see in the photos. It works great for us, we can pick tubes up off the ground without any problems and place them on any of the racks.
http://eatoncomputer.com/gallery/mai...geViewsIndex=1