RFB, SCAF and Hitman's tutorial
 

I was prepared to install RFB until I read that it is not compatible with SCAF. I use SCAF in the stock game so I do not have to spend the time to manually calculate the aspect ratio and convert it to AoB per Hitman's tutorial. Using the stock game's mast points to accomplish that task is damn near impossible. My questions are these: Does RFB have or accomodate a method of determining the AOB that is comparable to SCAF, or is following Hitman's tutorial the most precise solution (I prefer not to use the mast points of the target as a solution.)? If so, what is it?

Personally I never do any of that nonsense. In-game tools for me only. Plot two radar positions 3 minutes apart. The distance traveled in hundreds of yards is target speed in knots: 760 yards is 7.6 knots. Connecting the dots and extending the line in the direction of movement establishes the target track. You can be measure his course with tool help on and the compass attached to the ruler. Now the part you're interested in: the Angle on the Bow.

With the protractor tool, first click on the track ahead of the target, click again on the center of the target, and click a third time on the center of your submarine. The angle will be shown in degrees at the vertex of the angle, right by the target. That is your angle on the bow. You have speed, range, course and AoB. That's everything you need to put the bugger on the bottom.