I don't think it matters where you put your WB 02 sensor. I've heard that the least distance is about 24" from the head. I know my NB 02 sensor from the Fbody was only about 10" from the closest exhaust port. I'd set it up where you can have one sensor for each side. Tuners only tune from one exhaust pipe even using their high dollar sniffers.

If you run dual points to read from you can find out if you have a full bank running lean or not.