That's roughly what it cost me to do my 3 relay setup. I learned that Justin@Blackbear turns efans on for every tune he does, so I didn't even have to get it sent back in for a retune.

 

It shouldn't affect how long it takes to warm up. Since the t-stat is closed during warm up, not much coolant is running through the radiator.

 

I don't think you'll like hooking the fan relay to the A/C clutch output.
The thing will constantly kick on and off, and cause voltage spikes and screw up your idle. At least that was my experience with the standard 105 amp alternator.

Your better off hunting down the AC recirc door at the PCM for the A/C high speed option. That way it won't cycle so much.

 

It does. I've already tried that option with the early 99 PCM with the constant ON fan setting, no matter what you set it to.
These fans flow a LOT of air, and cool off the entire engine while doing it.

The truck will take longer to heat up and consume a lot of fuel while doing it.