Do you know max flow on the OEM injectors? That RC calculator should get you in the ball park on an answer if you know the fuel pressure difference from stock.
Another possibility, is injector scaling -- it may be there is more flow to be had, but OEM values for the injectors in the fueling maps end up giving you a higher claimed duty cycle that the OEM injectors are actually using.
Also, your AFR's sounds about right for your boost levels -- are you looking to run more boost or enrichen the tune?
BTW: I am very aware that you are
much more knowledgeable than me on many or all of these types of issues, so if I'm mentioning obvious/irrelevant things, chalk this up to I mean well, but my background in tuning and such is greater than some but far less than others...
anyway, just throwing out ideas to try and help
