ThayerRags: Thanks for adding the "Repair Jacks". I would have never found or known about them otherwise. I looked at them for a long time. I'm not sure exactly how they grip the machine but it looks like one would have to be careful. I agree with Rodney, as to choices of the three. It looks like the Boco balances the machine better than the others. The Wedge Lock gives a lot of possibilities for orientation, but imagine the stress on the lock mechanism at some angles.
Rodney: Thanks for looking and for all of your kind comments and interest.