I hadn't started the truck for a few days and needed to hook up to the horse trailer this morning and it was cold, 20°F, so I paid attention the the VGT position.
The truck jumped to 1000 rpms right after starting and the VGT was 93%. I turned the EB on and it went to 95%. I could hear the change but it wasn't huge.
I then kicked it back down to 750 rpms and the VGT was still at 95% with the EB on. Turned the EB off and it went to 93%. I then remembered page 2 of my CTS2 shows exhaust backpressure. EB on was 16 psi, EB off was 8 psi. Big difference there for only 2% on the VGT vanes. As the motor warmed up the VGT position trended towards 92% and the back pressure quickly started dropping 4 psi by the time the coolant was 80°F and then down to 2-3 psi at operating temp.
So, my 0.02, is that normal warmup doesn't warrant the need for the EB on as it already increases load some on it's own.