1st off, good pictures to show what I first mentioned in this post. Those notches are what i referred to in my initial post, and then don't allow the brake pads to fully retract, which also means the caliper piston doesn't fully retract. The edges of the pad fingers cannot "climb" out of the notches to fully retract from the disc faces. From comparing the two pics it looks like you ground down about at least 1/16" of material to get it smooth again. I bet once the notching starts, the action of driving forward/rotor runout/brake drag makes the pad ears fluctuate inboard/outboard to make the notching increase. I wonder if the brake pad failure was due to heat buildup. Which PS side pad was the failed one, inboard or outboard? Plus it looks like the pads themselves develop a notch in the corner wear they contact the slide rails.
So,...you maintained the same angle on the faces of the slide rails and simply ground them smooth? How much of a gap exists now on the rearward side of the pad edge/pad ears to the lower slide rail? Since any remaining pad drag will cause the pads to rotate to close the gap to the ground down slide rails, the lower pad edge gap to the slide rail will increase. Couple things though:
1. Since the lifetime miles on a vehicle is 99% going forward, and during braking the pads will want to rotate forward until the slide rails stop them, I'd expect the "forward" slide rail on each side of the Dak is worn/notched when the "rearward" slide rail is not worn/notched.
2. So you should only have to grind down the forward direction slide rail on each side of the truck
3. Could part of the pad function is also to support the caliper housing and keep it aligned onto the slide pins, so the caliper can't "rack" or twist on the pins.
Good idea to grind the slide rail smooth, as long as the caliper cannot twist/rack on the slide pins it should reduce the brake drag. Let us know if anything else develops. In wonder too, if you'll get less brake dust buildup on the wheels.