The first thing I would do is see why you get different readings on the O2's.
Do you think you might have an exhaust leak?
Or maybe a bad O2? You always could switch them for a simple test.
You must know everything mechanical is OK before your start to tune or you're wasting your time.
What is the deal with the back fires?
I can't stress enough the fact you could do some damage here and the first priority is to get some decent Closed Loop drivng conditions. At this point in time, WOT conditions should take a back seat here.
Do you show the K's to be active during idle and if so, what are the values?
Have you set your new cubic inch scalar?
What is your load at idle?
That ought to provide enough info to help the members get started to help you if you answer each question.
Grady