After a few incremental twists, you get to around 7.2-7.3 degrees. Good enough.
Take it out of the vice, grab a soft cover mallet and take your diagram to the floor, or whatever hard surface you want.
Take the AFT end now and mirror DWG 66 with the F-843-L. Hold the AFT end on the hard surface. The FWD end should raise off of the hard surface slightly with the AFT end entirely on the hard surface.
Start WHACKING the vertex halfway from the factory bend and work towards the AFT end. Don't be shy. I had to whack mine several times to get it to open up.
It seemed to open up better as I whacked it halfway from the factory bend and moved towards the AFT end.
Periodically check the angle with DWG 66 as seen in picture #3.
