Seat belts in 40's Cads

[gary griffin]

I was not sure if this should be in the restoration blog or technical but here it is.  I am working towards a very authentic restoration of my 1942  model 6719. I am being very diligent about authenticity but want to assure safety also. Has anybody studied this matter carefully?
Although it is sold as a 5 passenger sedan I will probably install 6 sets of belts. The lower connections are probably pretty easy to figure out?  If I want shoulder belts I am concerned about the connections. I am looking at installing the upper front  belts to a plate mounted on the divider. It seems quite strong and well affixed to the car. As for the rear I need some advice for sure.
   Who provides the belts that look good, matching the old style upholstery and are safe with good instructions and mounting ideas?
    Has anyone been down this road before and have any good advice?,