I'm obese but that doesn't explain the 5' 5" 100lb soaking wet driver that stands on the running board.
I used to do it with my Pete, but one rain soaked night in a dirt parking lot I hit a hole and #### near fell off the truck, that was enough for me.
Lean n look out the window .. open the door.. mirrors isnt about bein cool or obese its about the view
I open the door to move my mirror into position to see the rear of the trailer. Not to lean out and look at the trailer. I think only really poor backers that don't know how to use mirrors need to lean out the window to back.
Great big parking lot, that's empty! Try it. Set up milk jugs, or cans to back to. Takes a lot of practice. Don't try it in a cab over, LOL There are places my rig won't fit. Spotter truck is 30.00. Free if I want to wait hours. Do the math.
I learned to back an ol' Pete at school. It was easier to open the door but I kept my butt planted. In a Cascadia now I dont have to open the door, but I always roll down my windows and stick my head out.