60% injector duty is very safe.
Then again 1200cc injectors is huge compared to stock bmw engines.
The stock z4m injector does (according to bosch) 193 gram/min (n-Heptane @3bar).
Thats about 282cc/min @3bar (but the z4m pump runs at 5 bar I think? that would be equivalent 364cc/min)
Very quick&dirty calculation by injector difference: do you run at about 2.2 bar intake pressure? (17,5psi boost) (I took 90% max duty cycle as input from a z4m injector. If thats less, you're running more boost
)