Radiator Beef Up

[swissarmychainsaw]

Have you considered just adding an high performance oil cooler?
Like maybe with an integrated fan?

If I was towing, and NOT overheating (as you are not) I would do two things:
1.) add an oil cooler - you could have a thermostat switch and also a toggle if you wanted.
2.) Transmission cooler with fan and a thermostat switch.

Both of these are "bolt" on items, no re-engineering needed like with your rad.

If you are set on the radiator upgrade I would go to dual electric fans!
I usually like to keep my stuff on the stock side, but I bought a rig with a 6.0 and elec. fans, and it works great. (and all GM parts too...)