I also have the BD TowLoc and large pan with transmission oil filter. I find the shifts to be just fine at gross weight of 26,700 lbs towing 10,000 miles into Mexico and back.
I need to lock out the overdrive so I can reduce exhaust gas temps and increase engine speed at travel speeds usually around 50 or so. With tow haul and tow loc, it wants to stay in overdrive which increases temps and decreases fuel mileage.
Any other comments or advice?