The real concern here should be what will work for my car? There are many factors that will be different for each of us. The real trick is to avoid future difficulties. That means running lean and breakage as well as the possibility of having to re-do something that that could have been done right in the first place.
Building a fuel system without a good safety margin is taking a chance. That having been said, lets look at our options. What would be a good start? Obviously getting a good idea what your particular engine (not rwhp) needs. Fuel volume flow at rail pressure is the key. Rail pressure = aprox 45 psi base + boost. This number should assume 30 PSI boost possible for 75 PSI rail pressure, minimum.
This number could possibly be achieved by using a volt booster for the pump. These will typically be controlled by a pressure switch that only activates the extra voltage under boost. This might be a concern, since there is always the possibility of malfunction. A component that is relied on to the extent that if it fails, the engine would likely be subject to catastrophic damage is definitely something to think about seriously.
The possibility that the system is at or near the max capacity as advertised is also a serious consideration. These factors could result in running lean if diminished capacity was experienced. This could happen from the simple wear and aging process that inevitably occurs.
The very real possibility that there will have to be additional mods done to the system over and above just pump and injectors will increase with power level.
The return flow from the rail may become a restriction if using a high flowing pump. This issue is common, and will result in the inability to lower the fuel pressure at idle to the desired setting. Modifications to the return line are required to address this. The return line is only 1/4 just above the rear axle.
I don't see anything wrong with designing a system that is well above the needs of your engine for all of the above reasons. You don't need to know the exact fuel consumption of your application, but rather use an estimate and then over build the system to the extent that you feel comfortable with. I suggest overkill with fuel systems, since they can make or break your combination.