Sorry, I'm not set up for glass work right now. I'll try to get a scan of the directions posted tomorrow. I'm not sure how well they will scan because they are printed on yellow card stock. I thought I knew how it worked, but now I'm not sure.
The boat cam cleat idea looks like it would work best. It's like a plastic tie wrap where you insert the loose end and you can't pull it out again, only instead of a ratchet preventing motion, it is just friction. I think the size of the cleat would determine if you could attach a mandrel or a punty.
Speaking of repurposing, if you used to do leaded stained glass work, the stationary end of a came stretcher would work the same way as the boat cam.
http://www.amazon.com/Lead-Came-Vise.../dp/B004A6H47W
The spring loaded version might be better (since the non-spring loaded version works best if you use a hammer to set the grip):
http://www.amazon.com/Glastar-Spring.../dp/B00B1JX1S2
Here is one for less than half that price:
http://www.ebay.com/itm/CHOICE-Sprin...-/360862551701
The difference might be that a rubber cam cleat would probably hold a punty better. I'll try to test how well the came vise holds a mandrel.