I live in North Bend and have the exact same questions....I need pictures of how people have done it.....seems that they stopped installing them after the 85 model, so this is why things do not line up. I have the belts, but am now thinking I should buy some shoulder style and just mount to the back wall of the bed and tak weld in the seats via the mounting bracket it sits on. If the belts are secure, that the person won't go flying out even if the seats gave way.
let me know if you come up with something and I will do the same.
thanx, bob