Ed, that looks similar to something I made to get the spinners off of our Healey 3000.
I found a steel hammer in the trunk that the PO had used to smash the crap out of the spinners AND put them on so tight I ended up destroying two of them just getting them off. THEN I made a spinner wrench like yours (mine was far less fancy) and that worked well. When I sold the car I made sure that the wrench (and no hammer) was included.
I especially like the wood ball at the end of the lever to balance it off....