Fun with air/fuel ratio meters

[Coloradocobra]

I finally installed my Autometer air/fuel ratio meter last weekend to attempt to fine tune my new carb. I installed the O2 sensor about 4 inches downstream from the collector and 3 inches before the muffler on the driver's side. It immediately confirmed my rich condition and showed my idle swinging wildly as I was attempting previously to overcome a rich condition by leaning the idle circuit. A drop from 70 to 68 jets in front improved the idle and now my cruise mixture shows that it is in the "rich" range right next to "ideal". So, I have gone from way rich to just rich.

My question is, if I can drop one more jet size and get my cruise and idle in the ideal range without creating a lean condition under full load, is this desireable or should I leave it slightly rich? In Denver, the only place to go is even higher in altitude and it would seem that making it run just right down here would help prevent loading it up when making a mountain run.

Anybody have experience with these meters on a carbed engine? There was a great article on the web at one point on how to use these to tune Holleys but the link seems to be broken. I just want to make sure I don't mess something up.

Gary