Bosch "803" injectors

Am looking to use some Bosch 803 injectors on an M4 unit, I can see in the help that 803`s are listed for 45psi and for 75psi but am using a regulator of 3.5bar (51psi I think) are there any calculations to find the comp figure? or would the setting for 45psi be close enough? Thanks in advance Andy.