Here are some pictures of my setup. I found that the factory supplied bracket had quite a bit of flex in it; I could move the pedal in and out and see the Electronic Throttle Control (ETC) moving while its arm was stationary.
I was concerned that this would give some unpleasant driving characteristics; easing slightly up or down on the throttle from a given setting might initially do nothing, then yield a larger response with further movement.
As supplied, the bracket has a doubler at 90 degrees to the direction of pedal travel, but what is really needed is a doubler that stiffens things up in the same direction as the pedal travel.
To do this, I compromised and welded a 1/8" flat steel bar at an angle across the bottom of the bracket, butting up against the Tilton pedal assembly. This has removed virtually all of the flex in the bracket.
Also, as supplied, the pedal travel is only about 0.75" from idle to full throttle, due to the short throw on the GM ETC. Per Fran's suggestion, I added a vertical plate to the arm of the ETC with the dimensions as shown in the pictures. This provides about 2.5" of pedal travel, allowing the set screws on the Tilton pedal assembly to be used as stops.
Some of the pictures were taken while things were temporarily held together; I'm missing the penny washer to trap the rod end and was using regular nuts instead of self locking ones.