How much power do you intend to make? That is the deciding factor, not cubic inches.
All HP figures are Flywheel HP, no NO2 or forced induction.
325 HP - 24 lb injectors - 120 LPH
350 HP - 25 lb injectors - 130 LPH
375 HP - 27 lb injectors - 140 LPH
400 HP - 30 lb injectors - 150 LPH
Increasing the pressure increases the flow rate for the injectors. A 24 LB injector can flow 27 LBs if you turn the fuel pressure up from 40 PSI to 52.5 PSI.
Using a bigger pump than is required is OK, since the regulator returns the excess fuel to the tank. If you increase the pressure past 45 PSI, go to the next larger pump size, since flow rate decreases with pressure increase.
I agree with jrichker, a larger pump won't hurt anything. Since the price difference isn't much between the different sized fuel pumps, I will soon be getting the 255lph pump. It's not much more and if you make future mods, you will already have the pump to support it.