It depends mainly on two things imo. Do you have two pumps or only one. The pump you have can it pump wort (march/chugger/lg). Also your water temperature and batch size, would change the ideal solution.
If you intend to pump wort i would use the pump to push throught the chiller, these magnetic pumps dont really pull or suction the liquid.
Edit : misunderstood your question, if you recirculate wort throught the cfc and back in the kettle you can adjust the ouput of the pump/water faucet.
If you pump the water are you going to gravity feed the chiller?