[48richard]

The first thing I did when I bought my truck was to install 3-point seat belts, from LMC.
You are right - the driver side one is not a direct bolt-in unless you are happy with the belt rubbing on the tank.
I made a pair of brackets from 2"x2"x1/8" angle. The bolt into the original bolt hole, but I also put in second bolt right below the retractor. You will need to open up the angle of the angle steel a bit from the 90 degrees to make everything fit right.
You don't need it on the passenger side, but it just seemed better to have both sides the same.
Hope this helps.