4 Point Harness and Harness Bar Question

[sixpax]

I know, search is my friend. Problem I have is that I can't find any pics or explanations that educate my slow, old mind enough to understand a few things.

I get that the shoulder straps go through the holes in the back of the seat, and over the harness bar. One thing that puzzles me is on the end of those straps is a heavy metal bracket with a hole in it like it supposed to mount somewhere. I don't think it goes over the harness bar and then all the way down to the floor to mount on maybe the seat bolts ? Other option in looking at some pics is maybe it loops around the harness bar (so would have to have those belts on the harness bar somehow and then mount the harness bar) but if that's the case then the big metal mount things just dangle there ?

Also in my infinite wisdom (sic) I have since learned that NASA and some others will not allow 4 point harnesses in HPDEs ? If I read the rules correctly. If so, is there an easy way to convert a 4 point to a 5 point ? Like an additional add on belt ?

Any input appreciated ... the harness bar is similar to the NRG one.