I can't very well say what is what with 6.0L tuning. I have Sniper Delta Force for the 7.3L and would highly recommend not getting it because (and keep in mind that this is for the 7.3L) it is so incomplete it's not funny.
Not knowing what to tune in/out for CNG, I can't help you with any tuning data but I can say that nothing
should need to be changed as far as fuel rates go. Injection timing maybe just a bit but the fuel rates should only need to be changed by your right foot (less accelerator input for any given load/engine speed).
I could be way off, too.