Colortune & CO meters

[Formeister@domain.elided]

I'm getting ready to fine tube just the idle adjustment on my carbs after an 
engine break in period and was wondering if anyone has any comments or 
experience in the use of "ColorTune" spark plugs or CO meters to set this 
mixture on Webers.  The color tune plug sounds good as you can see the 
combustion flame and adjust each barrel accordingly.  However, I expect this 
is very subjective.  On the other hand an inexpensive CO meter is about three 
times the cost ($50 vs. 150) and I'm not sure the cheaper ones would be very 
accurate.  I know I can get it in the ball park and have it run well by the 
usual methods but I'd like a little more accuracy w/o resorting to a 
dynamometer, 1/8 to 1/4 of a turn is not perfect in my book.  I tried making 
a testor out of a 'used but good' heated O2 sensor I had lying around which I 
can slip up the tailpipe but the readings on a digital voltmeter seem to jump 
around too much for me to make any sense out of the reading.

All comments appreciated,

Frank Formeister

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