NB tuning does work. Well to a degree. Small degree. Its just that many advocators of WB (raises hand) allows you to tune in all areas of your map. I normally shut off the nb, fatten up the mixture, and run it about 13.8 afr to 14.2 afr cruise, 13.2 WOT.
If I ever get time I am going to narrow down the closed loop portion of the map to just where I cruise on the highway at and taper the rest of it back to richer. Utilize my 02s and leaner mixture at my cruise rpm/tps and richer everywhere else.
Regardless tuning will get you running cooler, more HP, less backfire, smoother roll-on, etc.