55.2-59 Three point seatbelts

[leegreen]

I used 2005ish sierra seats with integral belts. Seats bolted to floor with 4x4 plates sandwiching floor (rounded corners, bent back edges Gr8 bolts)
I'm happy/comfortable but I know these seats are not everyone's cup of tea.

Locations; Do you have your seat and steering wheel installed?
I'd get comfortably located in the driving position and place the belt attachment locations relative to my body using some modern daily drivers as a reference and paying more attention to the angles than the distances.

I'm not familiar enough with the TF cab to give specifics, but for the 3rd point you are going to need to get a large plate with a nut for the belt attachment welded to the back of it up inside the inner skin of cab in the area of the pillar and plug welded into place.
-maybe- glued in place if you have a finished interior, the important thing is that it stays where you need it and has a large enough surface area to stay behind the sheet metal in a crash.