Fuel Pump Control

I have a 94 mustang with a built 408w in it. I am in the process of setting up my engine control unit (Vipec V44). On this unit I have an auxilary output that will switch a relay for my fuel pump (inline A1000 Aeromotive pump). So equipment wise I have a controller capable of Pulse Width Modulation, a very fast switching solid state relay, and a pump that is more than enough. My question is that I want to have my pump slow down when I don't need the fuel supply so what is a good choice for switching speeds and duty cycles. The pump is rated to 1000hp and my engine makes 500hp and 650 on the juice.

Hz:??????
Duty Cycle(500rpm): ???
Duty Cycle(1000rpm):???
Duty Cycle(2000rpm):???
Duty Cycle(3000rpm):???
Duty Cycle(4000rpm):100%
Duty Cycle(5000rpm):100%
Duty Cycle(6000rpm):100%

Thank you in advance