SNIP <I have the Vertical card, but have major errors in it.>

The vertical card compass requires swing adjustment as I'm sure you are
aware. A brass screwdriver is included in the package as I remember.  Make
sure that there are no ferrous sources of interference. My vertical card
(PAI-700) performed well unless I was in a diving spiral (voluntarily) when
it would "catch" and eventually release.

Richard Freilich
Now planeless