Question about relocating seatbelt mounting locations.

[scherp69]

As the title says, I have a question about putting in a custom interior and relocating the stock seatbelt mounting locations. I'm installing GTO seats, front and rear, into my 68 Acadian (Nova) and may not be able to use the stock seatbelt mounting locations. Are guys just welding on new nuts for the seatbelts or what is the proper way to do it. I'd also like to put three point belts in the rear but there are no stock mounts for the shoulder part. Any advice would be greatly appreciated.