I'm going to make another lazy post again and show the instructions I wrote for CJ's. But when I put so much effort and detail into writing these instructions, I just don't feel like writing them again.
Three point seat belts are an important safety upgrade for any car that doesn't have them...right up there with installing a dual master cylinder and maybe even power disc brakes. And there's a lot of jabber online about which seat belts to get, and how to install them, up at the roof or down lower on the inner quarter. I opted to go for the lower route as it felt better across my shoulder, and I think it looked kind of bad with the seat belt hanging in the window when it wasn't in use. A lot of people say something about spinal compression, which I'm about to baselessly go on record and say is nonsense. While I could be completely wrong, my gut feeling is somebody, somewhere on the internet stated this, or maybe even pondered it, and then everybody else picked it up and ran with it. If it were a truly dangerous configuration, I can not see how the NTSB would still allow for such a configuration to still be marketed and sold, or even approved by NTSB.
All that rant aside, here is how I installed these.