4 pt Harness mounting/strut mount insulator problem

Well I finally got around to mounting my seats and 4 point harness and ran into a couple of snags. The seats are pretty well too wide for the car, but fit snugly. The bad part is the rear strap on the harness is way too long even with the slack pulled out. Is there another way to mount these with the set-up I have and not snap my back?

I know many people wrap there's around a strut tower bar, but mine isnt set up that way. Assuming the car runs and drives fine after I finally get it going I will probaly just by a regular seat belt set from MSA. I just dont like this harness, but it is what came with the car.

Also, After making sure all of the rear suspension on my 72 was tight I found out the rear threads were all buggered up. I tried to reform them, but I still can't get the nuts on good and tight (they are doubling as a harness mount for now as well).

Is there a way to replace these bolts without buying new insulators? Also, what should these be torqued to? My haynes manual doesn't say.

Thanks