Program 9, from The Doorhanger's DVD, Hanging a New Door in an Old Jamb, from the 10-program Mastering Finish Carpentry Series by Gary Katz. Available now on YouTube for FREE! The video technology is old, but the professional techniques and tips stand the test of time.
Here's a link to drawings and measurements for the door bench:
https://www.dropbox.com/s/alwc68xcqf263kj/KATZ%20DOOR%20BENCH.pdf?dl=0