It's a little late for me right now, but if read you correctly switching to a +/-5V or +/-12V supply with Vref at ground that should solve my problems. Vref will be more than 2.25 from the rails if it remains at ground and the output of the AD595 that will be between 0-1.25V will be more than 1.7 above -V (at -5 or -12).
I will give that a shot tomorrow.
For amps on hand, we have the INA126, INA128, INA129, and a few useless surface mount ones that I can't prototype with.