Nhra seat regulation help please

[GT3FC]

Not too long ago I got a corbau fx1 seat.... Thus seat is a fiberglass seat so in order to be Nhra compliant I need a seat back Brace that attaches to my roll bar.. My problem is corbau put a single reinforced bolt in the back of the seat but I can not find a seat back Brace that will bolt to that single bolt even with drilling the mounting plate because the Brace that runs back to the roll bar is in the middle of the plate.. Anyone have any ideas on a seat back Brace that I can use? Also is the single mounting point on the back of the seat even Nhra legal? Or do I need 4 mounting bolts? I can't drill into the back of the seat for more mounting points because according to corbau I would just be drilling straight into fiberglass which woulnt Brace anything.... Anyone have any ideas? Also I would like an adjustable Brace... I am afraid to get a fixed Brace in case it might fall too short also I would like to be able to still move the seat back and forward... Anyone have any advise other than gabbing up my own seat back Brace?

 

[GT3FC]

so I bought the materials to make a fixed brace today it basically consists of two thick long L brackets that will be welded to each other to set the correct length then one L bracket will bolt to the seat and the other will bolt to a ring clamp (dont know if that's what its called) that will clamp onto my harness bar ill post up pictures when I have it all welded together and in the car