I will throw in a couple of "data points" here.
-gas is 94 octane with (up to 10%) Ethanol
-Wideband is in the (Cobb) Downpipe bung
-Injector scalar is used to change AFR
First plot: Injector scalar changed by 5%.
Second plot: Injector scalar changed by 3% and then back (to check repeatability). This group of plots is not directly comparable to the set above as the ignition curves are slightly different.