New 3 point seat belts

Hello all,

Thinking about replacing my front seat belts in my 1974 Duster w/bench seat. Seat is out getting redone and I'm thinking about replacing the double retractor 3pt belts with one of the new one retractor set ups. Has anyone used these, if so, how did they hold up? How do you remount the cover were the old retractor was inside the rear side panel? The cover currently screws to the bracket of the old retractor system in the side wall. Without a way to mount the cover there would be a gaping hole where the belt anchors in side the side panel???

v/r
Ron