Yep. I did this recently. Like kube said, measure, then measure again, then step away for 24 hours. Look and measure again. Maybe do that 3-4 times and then break out the knife! I did just what you are saying and made a template from the left side. Really hated cutting my original car but I drive it a lot and safety matters to me. These cars aren’t safe to begin with so my philosophy has always been to do EVERYTHING I can to make it as safe as it CAN be. I don’t remember a bracket….id go out and look but I just dropped the car at the interior shop this morning. 3 months with no ford!