Gunson gastester

[Skip Osmundsen <gosmund@bellsouth.net>]

Hello all,
I'm thinking about getting a Gunson gastester (the basic model), and
would like to know if anyone can attest to it's accuracy.  I'm tired
of the tweak-and-pray routine and the multiple trips to the State's
tailpipe sniffer. Can I tune with one of these things and then be
confident to pass?  I never have a problem with the HC readings, just
the CO which is tested at idle only.
Thanks for any info.
Skip Osmundsen
'76 TR6 (finally off the stands and trying to get thru emissions).