basically at a steady cruise, stoich or slightly rich, 14.0 or richer is fine. for part throttle you need to be a little more on the rich side normally but it really depends on the rest of the combo and how efficient it is. your right in that the WOT A/F should be in the 12.5-1 range and the rest under part throttle light to medium load should be in the, well, let's say 13.5-14.5-1 range.