How come Arthur Jones was a shrimp? Why was Gary Jones a pudgy guy with all those Hammer Strength machines he made? Seriously, what Vince accomplished with that machine is some serious engineering. A bicep machine with resistance when you supinate twisting the grip that was talked about for ages during exercise machine development.
We hang a lot of shit on him, but to be fair to VB it's quite easy to look at something and then tell the guy "Hey, you know what you
shoulda done?" Working from the ground up is a whole different story and I could see simple bio movements becoming surprisingly complex to translate mechanically. I'm sure he's had a lot of 'shoulda' ideas of his own since then that would pare down the complexity of it. I shudder to think what he spent on machining, and I think some more headscratching time on design and discovery of mechanical principles would have paid dividends for him, but I still respect that he went out and did it.
Tbh, I reckon simply holding a dumbell off center is the best solution but that's just one flotsam's opinion.