I use a single 17” 2-speed Derale fan and shroud combo that fits my Summit radiator like a glove. I have it set up on a temp switch to come on at 165 and shut off at 150. Fan runs on the high speed when the engine (and alternator) is running, and the low speed when the ignition is off for the lower amp draw. The “key off” circuit also includes the water pump.

My car sees regular race duty and a few cruise miles in the summer, which means idling in traffic in warm to hot temps. I’ve never seen it over 200 since going to this setup.