where to place WB o2?

On a V8 engine with a NB o2 on each bank, is it OK to replace one NB with a WB for tuning?  Or is it better to add a dedicated bung somewhere for the WB?

side note:  there are some guys out there that are *still* developing tuning and flashing features specifically for the 94-95 LT1 "$EE" controllers. it's pretty crazy.

You should be good with the WB on just one bank, you really only need that to get your trims set and then the NB should keep everything in check once the base fuel map is smoothed out. The new, hot V8 swap ECU, the Holley Terminator X, only has one WB to control the whole system.

A port that you keep capped off on the other bank may be helpful for trouble shooting if you are having a fueling issue but is also another weld and another potential exhaust leak.

In a perfect world you want to be in the Y pipe merge, single point AFR monitoring is more or less looking at an average for the number of combustion events occurring in a revolution make your sample size as big as possible. That said lots of perfectly good tunes have been accomplished by kicking one NB sensor out. AFR sensor (note AFR not o2) after a cat isnt a huge deal either. Make sure you have a good 6" to any potential leaks to avoid idle related head bashing. 

The pre OBD-II LT1s had dual oxygen sensors?  Somehow I remembered them having only one sensor.  Maybe I am thinking of a different engine.

You should be fine.  After all, it is not as if you are tuning separate bank1 and bank2 tables.  If you wanted to be a super weenie you could tune it to one bank, switch sides, note if there are any places more than a couple percent off, and split the difference, or shade it so you are perfectly tuned to the bank that is leaner at whatever point, or whathaveyou.

I stopped worrying about the last couple percent after tuning a Ford   Due to the way they work, you will never get closer than 7% or so.

The other thing is that if you're not doing a crazy turbo setup, the WB can leave after you have "tuned."  That way, you can regain full NB functionality.  You also don't have to wait for the WB to decay, which is not cheap . . .