A normal O2 fluctuates too much, it is best used for tuning for or near stoich for low load and idle conditions (using the crossover point). A normal O2 sensor says whether a condition is rich or lean, not how rich or how lean.
A WBO2 has a linear response that actually corresponds to an AFR. Switching it to 0-1v instead of 0-5v will lose some resolution, but it will still be a linear response.
I don't know if you can do it with resistors though, there was a thread on doing something similar for using a cheap 1-wire AFR gauge with a WBO2.
Mario