Rev it until the valves float, then grab the next gear
I have about the same shift points as eaglescout526. If I need to cruise at 40, I’ll grab 5th then, but if I’m accelerating, I rev it out some. That said, you can shift anywhere up to redline. It depends on how the truck is being driven at that time.
For what it’s worth, my truck is a 4.0 on 31s with 4.10s.