Actually the knurled knobs are not for pinching (there's a joke in there somewhere but I think it's better not to find it) They are simply handles for pulling.
The good news is that, thanks to a large and strong gentleman at the PHSNE show here in Boston, I got the thing to work. Just needed some "persuasion." I took a roll with the Rolex back- half with this Onito and half with the Rietzschel Clack that I have. I have yet to print the results, but the Onito seems to be quite nice. The next step is to try some sheet film in it. Good buy, I think, for $37.50.