Curious what system are you using to change the engine calibration?
With the COBB system (at least) you can monitor the HPFP % utilization, which should give an idea of how far or close you are from the pump capacity. With the stock injectors it is possible to go beyond 80% utilization on pump gas already. I'd keep a 15% safety margin here, to have room for extra fuel dumping e.g. for knock quenching and/or temperature control. I'd never want to see more that 85% pump capacity in normal use, and that's going to be at peak boost around the peak torque RPM.
As far as adjusting for the new injectors you need to tell the PCM the new flow rate, which is "Fuel Tables -> Fuel Injectors -> Fuel Injector Slope (Flow Rate)" on COBB, and defines the fuel mass flow vs. rail pressure. The PCM uses that as a basis for the injection pulse length calculations. It's a single and simple change if you have the data from the injector manufacturer.
Otherwise you can multiply the existing curve by looking at the flow difference between stock and replacement: new flow / old flow gives you a factor >1 that you apply at every point of that curve, but make sure the flow data you have for each type of injector is referring to the exact same thing (same pressure and same duty cycle). Injector manufacturers often rate their injectors using different methods.
This is the most important but you should also check the other parameters: opening time, closing time, minimum pulse width. All DI magnetic valves in the same form factor as the stock ones should be in the same ballpark e.g. 500 microsec but it's worth checking.