[sunman]

The roll bar in Marks photo looks like a cosmetic bar bolted in.
Real roll bars drop down to a 3”x3” angle, that you have to add, underneath the tray further back. Your inside bar sleeves are welded to this angle.
There is area to add plate outside of frame rails for the outside or single hoop roll bar legs.
Attach harness to roll bar because:

Shoulder belts should be attached level to shoulders and not be redirected by seats
Lower bolt location is unsafe and in an accident can cause spine compression

Party On