I have Fullsac TD's and am adding a DJ Wide Band Commander.
As I understand it .... the O2 sensor needs to be within 30" of the rear header flange (?).
Any suggestions as to where to mount it's bung so it doesn't stick out like a sore thumb?
Pictures of your install would be great.

 

but the O2 sensors for the exhaust are withing about 12 inches of the header joint on the 09 FL's and right next to the right side footboard on the 10's and 11's
The PCV doesn't even use the O2 sensors so are you sure your does?

 

No my doesn't, but I'm adding a Dynojet wide band commander so I can tweak my PCIII maps using the air fuel ratios at different throttle positions, that the WBC provides via the LCD-100 data logging capability, while riding.
To do this you need to mount the WBC's Bosh O2 sensor (the same sensor the WBC2 uses with the PCV and LCD-200 to add auto-tune to the later bikes) in the exhaust.
What I'm hoping somebody can provide for me is the 'total' length of the Bosh sensor, from the exhaust to where the cable attaches (including the bung).

 

I had a Fullsac with the O2 sensor bung, which was mounted on the inside of the "U". Rather than installing a sensor bung in the fullsac you have, you might consider selling it and buying one with the bung already in place. It might save a bit of hassle and look better, too.

I'm not at all familiar with the Wideband II. I have the autotune on my bike, but I had to go to PCV to use it.

 

I couldn't find any pics of my fullsac installation, but in this pic, you can see the rear O2 sensor on my Rinehart exhaust. The sensor kind of angles down with the Rineharts, and I think the fullsac was similar. On the stock headers, the O2 sensor was more horizontal.

 

I am under the impression that the sensor should not be mounted beyond more than 10º down from horizontal, to prevent moisture from causing an incorrect reading.
Maybe this is only a concern at start-up, and becomes a moot point as the bike comes up to temp. (??)

I'm hoping I can mount it in the header pipe so it parallels the starter, just after the second curve (from the flange) between the two heat shield clamps for the first and second rear cylinder's shields.
As best I can determine, the sensor is about ~2.5" long and 'should' fit in there .... if I can find a welder that can place the bung in my exhaust so it will be between the two heat shield clamps, and at the right angle for the sensor.