2006 LS4 Tune into SSR bank 2 -100 How do I turn on Bank trims?

[04colyZQ8]

I loaded a 2006 Grand Prix 5.3L tune into my 2006 SSR file, to get the fuel gauge to work right. Seems to be working well so far but I'd like to turn on Bank 2 trims? I have the O2 sensor wired up, to the pins from a SSR, and turned on all the Bank 2 codes. My scanner still reads -100 bank 2. This is because the LS4 uses one O2 sensor in the middle pipe. But I'd like to fix this

How big of an issue would it be to just run the one O2 sensor? Even though my Y pipe is way down stream of the O2 sensor?

[04colyZQ8]

Here is the TUNE