You might find this useful:
http://robrobinette.com/autometer_af.htm Not sure how consistent the temp is on our O2 sensors, but I wouldn't be surprised to see a fair difference between normal driving and hard acceleration. This will change the 'ideal' O2 sensor voltage that you're shooting for.
Therefore I don't think it's as simple as saying "you need this exact voltage". Given that normal (stock) Contours seem to run >0.9V I would say that is probably the safest route.
Note that the GN guys evidently look for voltages in the 0.75-0.8 range. And they're running turbod cars. This is probably caused by the higher exhaust gas temps that they see thanks to turbocharging [notice in the web link that the O2 voltage goes down for a given A/F ratio as the exhaust temp goes up].
-Lance
