Checking CIS Mixture with an auxiliary O2 Sensor?

[2ndTARGA]

Hi: (I posted this earlier with a more confusing title - hope this is better.)

I have this small box that Haltech used to make - it reads air-fuel ratio directly from a dedicated O2 sensor. Has anyone had success using something like this to check or set the mixture on a mid-year CIS car?

I've searched on this and found mention of someone who may have built or used such a tool. Any advice would be appreciated on how good an idea this is and whether AFR correlates well to proper CIS mixture setting.


Thanks,

Ron