I'd stay away from ITB's for your application, unless you want to spend the money for TWM's or something SOLID. RC Engineering (injector shop) has a good injector sizer. I'm guessing something around 25 lb/hr will be fine. I'm using 30's/310cc and they're plenty big for NA.
Wideband would be a nice addition tho. Wanna check into going in on one?
Yea, not red hot on ITBs for Rally. Though, it'd be rad, I'd like to keep tuning down to a min in service.
It's obvious that the measurements you are throwing up there to identify injectors are flow/volume. Yours are 30lbs per hour at 310cc? Do you notice unburned fuel/detonation with larger injectors etc?
Pardon my ignorance, I assume wideband is a measurement device for assistance in tuning? What do they go for?