Retro Fit of Inertia Seat Belts to 1970 SII OTS

I wish to do something similar to Chris Vine ( http://etype.chrisvine.com/ ) , where he fitted new seat inertia belts onto the vertical front wall of the boot out of sight in the tub! I wonder if anyone has done a similar thing with after market belts bought in NA . Is Chris V on J-L …it would be great to contact him…he has an excellent web site but no link to him that i could see.