I tow with the Programer Max Energy by Hypertech, set to level 3 and 114HP Gain. Its an awsome programer, been using it for over 3 years with a stock truck. The torque is at least 20/30% higher at the same speeds.
I found that at 10PSI Boost gives me best MPG and I can do most hills quit well with the 15500Lbs 5th wheel in tow. MPG decreases very quick when the torque/load goes behound 55%.
The best tool to improve MPG is the scangaugeII. It will tell the whole story about Gas mileage and where it best to operate at. I get all kinds of other drivers assumptions but my Scangauge tells me everything I have to know. No one else or other method of measurement come as close for $165.
For anyone that have programers and MPG problems its the right tool. Because it can be calibrated at every tank. Mine varies from 17 to 43% differential with the pump, but thats ok because once calibrated I can find the fuel station that are rubbing my money. At Home there are 2 out of 3 Fuel station that are robbing me of up to 10% so now I fuel at the one that give me my moneys worth. Pay back on my ScangaugeII is done quit quickly that way, plus its a Scanner when required and an EOT and ECT gauge with digital Indiucator for many other gauges.
I bought it to tell me where the truck was most efficient at and for protection because I knew the 6.0L had to be watched when towing with the programer. EGT has never been a problem while towing with the Max Energy set at level 3 for me.