If you put holes in your fan shroud you will kill the effectiveness of it and might as well take it off--the OEM types with the rubber flaps let air pass thru from vehicle motion but when at slow speeds or stopped will close off and make the fan suck thru the radiator.

I'll just add a couple more notes----use circuit breakers in the current supply lines to the fans, not fuses or fusable links---place your switching mechanisms in the ground circuits for the relays so you don't need high amperage passing thru your switches
You can run a high guage wire directly from your alternator to the relays for the fans so the current doesn't need to go thru your dash---

Don---maybe not in your case---but running without side panels on your hood can cause a turbulance that will destroy the effective differential pressure at the radiator and kill air flow---the best is hood panels and louvers to let the laminar flow down the sides create a suction