I think you need to consider whether the door will twist around the hinges or whether it will move where you want it to. The hinge supports inside the door are not all that strong, in my case they were broke. After all the time to repair them I wasn't about to try to use them to hold the door steady while trying to bend it.
I tried exactly what you mentioned on the driver's door after finishing the work on the barn doors. I blocked the door and then pulled on the lower rear corner. I ended up twisting the door on my first attempt and had to spend a looonnnng time fixing that problem in addition to the original problem of the door did not aligning properly. I'll admit I don't always know what I'm doing but the driver's door was a hard lesson.
