Flex fuel sensor

I have a 5.7 VZ Commodore which has a large number of tables to adjust settings for 0 to 80 percent ethanol.
Instead of using the sensor input for it's intended use, I think that it could be used as an 'on the fly' adjustment. Admittedly for only one parameter at a time.
One possibility would be. Use the input to tune the traction control.

My question is, what is the format of the sensor? (analog, PWM) and how does it connect to the PCM? (which pin).
Worth some thought?
Cheers, Steve.