After much advice from Tom Lear (thanks, Tom), I decided to thread
the mounting nipples of my Dynavoice striker units.  I used a 7/16" x
14-threads/inch die, and was able to buy a large box of matching nuts
at the local Ace Hardware.

The threads cut well in the plastic, but I found it best to nail my
die holder to the side of the workbench and twist each striker unit
in my hands.  Be sure to cut clear down to the base of the nipple.

It's much nicer to have a reversible mounting system (nuts) than those
nasty clamps.  Tom knows what he's talking about when he says you'll
have to remove and re-install each unit a few times.  Only disadvantage
is that box of nuts adds a few more pounds to the machine's weight --
but helps keep it on the keys!

If you have air supply and/or control nipples breaking off the units,
I worked out a nice scheme for repairing those too, using brass tubing
"stents".

What I haven't done yet is gin up the nerve to split a unit apart and
work on the pouch or valve block, which you will most likely have to do
for some notes.

Good luck, Mike Knudsen