I could not find how Chuck did his... I found a YT video of course... It should be set to start at the "reverse method". I assume he means it is reversed from when you don't know what the desired angle is ahead of time.
If the 5 degrees is the actual bend you need on your airplane, you will want to cut half of that off each side of a line drawn around the tube. So 2.5 degrees each side of a line that is perpendicular to the long axis.
Below is a pic of a test cut out of paper. The pie cut wedge looks to be about 6 degrees but the gap closed up nicely.