http://www.speedhunters.com/2014/06/tak ... t-answers/
Lijkt me wel toepasselijk.
When mounting shoulder belts to a roll cage or harness bar, the optimal angle of the belts (from the horizontal plane) is between 0° and 20° downwards from the top of the occupants’ shoulders or seat back opening. When a rollcage or harness bar is not available, installing a multi-point harness to the rear OEM seatbelt anchor points (D & E) an angle of 45° downwards from the top of the occupants’ shoulders or seat back opening is acceptable.