Yeah Paul, you've got it; watching EGT, transmission temp. coolant temp. RPM and lastly MPH is how you operate a diesel for efficiency and long engine life. Put the EGT sensor on the exhaust system down-pipe, just past and below the turbo so the metal chips from the hole you'll drill fall into the exhaust system not the turbo.
If your tranny tends to get too hot, (some folks say above 200 degrees is best to be avoided) step up the size of your tranny cooler or add another. After I melted my stock tranny I purchased a heavy duty version from the stealership (kinda shows Ford realized their regular version needed beefing up!) and removed the 9 pass cooler they installed with it and installed the 32 pass Explorer cooler; I've never exceeded 175 degrees since and the tranny came with a 3 year, unlimited mileage, nationwide warranty!
I have had to slow down and down gear going uphill when the coolant got to hot but have yet to modify the engine cooling system because I've not found anything I feel will really help.
Oh, and for RPM range I go down to 2100 because that allows me to down gear without over revving in the next lowest gear, try it and see if you don't feel you're still making good torque in that lower RPM range too, that's what diesels are known for and I think the towing programming is meant to bring that out. As for the high end of RPM, I also go 2800 which is still safely 20% below red line, same way I operate the diesel in my Tug. Well, there's 20 years of diesels in a nutshell!
Diesels; when it absolutely positively has to be there!
