Clamp the valve stem in a small vise, with the jaws lined with wood.
I modified a cork screw by turning it into a collar puller.  I raise
the collar enough with dull wire cutting pliers, being careful not
to cut into the valve stem.

Slip a 90-degree bent piece of metal with a slot cut into it
underneath the collar (this is now the business end of the cork screw,
instead of the spiral metal piece it came with).  Push down both
handles of the cork screw and the valve stem collar comes right off.

To insert the collars, I press them on using a small drill press.
I would use double the amount of valve wobble on a Lester as I would
on a Standard.  The reason I believe the Lester requires more wobble
than the Standard is that it's manufactured with less precision.

Bill Maguire