Do you actually use the 'high speed' on the big fan? Wondering if its worth the hassle of wiring it up. Curious if any of you went through the time to wire both speeds up and never even really use it. I havent wired it up yet at all, just fitting it to the radiator last night. Once the temp. sender kicks them on...do both fans run at once? The small fan is only one speed, while the big fan is a two speed. I assume the big fan is normally on 'low speed'? Is there any reason to wire it up on 'high' all the time instead of 'low'?