Stock Seats and Cage/harnesses question
The stock seats really don't have any material to bolt them to the crossbar with, any track tech guy that is telling you this doesn't know what he's talking about. I have yet to see a Stocker with the seat bolted to the crossbar.
The belts should pass through the seat slightly below your shoulders so it can continue on a downward angle to the crossbar to keep you in place should the unthinkable happen.
The Stock Eliminator rules are in the same NHRA rulebook as the general regulations that you quoted from originally. It says nothing about bolting the seat back. I still say that general regulation 6.2 is refering to aftermarket or fabricated seats, not the stock seats.