To answer MMD 000810 from Bob Lemon, here are the measurements for the
Cremona mandolin attachment.  There might be some variations out there,
but most will probably be in this range:

The overall length of the paddle is 2.1875 inches.  This is including
a new buckskin bumper that is glued around the end to contact the
shank.  In my Cremona the distance between the shank and the strings
when the hammer is touching the strings is 2.3125 inches.  Therefore
the space between the mandolin paddle at rest and the strings, when the
hammer is touching the strings, is .125 inches.  The width of the
paddles is .4688 inches.  The spring is a very light spring, probably
a light jack spring.

I hope this helps with the basics.

Brian Smith