Specifically I'd need to adjust output to +1V when Vs is +3.3V.
I would do this by tying Vref2 to GND, and pulling Vref1 to +3.3V with ~120k resistor. Assuming 100k internal resistor in Vref1 and Vref2 that should work, but does it lead to noise etc problems?
Thanks,
Ari