CIS has higher system-pressure than EFI. CIS uses something like 7-8 bar and EFI uses 4-5 bar.
911 SC has one pump and runs CIS.
911 Carrera has one pump and runs EFI.
930 has two pumps in series and runs CIS.
There is no pump in engine bay on 930 or SC or Carrera, shiny thing is pressure accumulator.
One 044 pump is probably perfectly OK for 500hp as long as you run EFI, if you plan to make lot's of power with CIS, you would need twin pumps as you need both flow and pressure.
With other words, SC and 930 fuel system aren't the same, except that both use CIS which needs high system pressure. If converting to EFI, arguably one pump can be used.
Thank you for your time,