You can use narrow bands within their range to tune VE tables (or MAF Xfer) in closed loop (i.e. part throttle and idle). I know with the Fords, the first thing you do is turn off LTFT correction for WOT, as it can quickly make things go badly. Focus on STFT and use LTFT as a gut check. The GM guys are a little different in that their LTFT corrections are actually accurate and most often are applied to WOT fueling with good success. Still doesn't replace the need for a wideband to tune WOT or any other open loop scenario. That said, WOT tuning is still dependent on a wideband, among other things, and all of the GM tuners that I know still use a wideband for WOT tuning.