Proper exhaust tip placement

My 68 Cuda didn't have dual exhaust from the factory but I have installed a dual exhaust system and am ready to install a set of factory styled exhaust tips and factory style hangers but not sure exactly how far back to locate them. Can anybody post a picture of exactly where the hanger is mounted to the frame rails or anything that shows how far they stick out?? I assume they end somewhere close to where the bumper ends??

Thanks, Tracy