Face Form Angle - Simple Chart

Face Form Angle is the same as the Bow Angle of a spectacle frame front. herewith I wish to share to basic methods.

Improvise with a simple chart.

Frame Front Reference

1. Place the frame with the top rim of the frame on the chart as shown in the picture.  
2. Ensure the left bridge/rim joint is position on the little black dot somewhere in the middle of the chart.
3. Whilst keeping the left bridge/rim joint in that position, move the right rim so that the nasal and temporal ends of the rim are position on any of the same broken lines.
4. Simply check out the line that meets the temporal end of the left rim for FFA values