Sub frame connectors

Convertibles and Big Block cars with the 4 torque boxes.....This is a little trickier at the rear to attach the frame connector.
The US tool item works, but not what I want. I am looking at Chrome Molly round tubing, slight bend to follow the floor and incorporate the driveshaft loop. This is for my 69 Dart Convertible. Convertibles really benefit from the frame connectors. I figure round tubes place just right will allow emergency brake routing better.... any thoughts, anyone tried?

Most round tube connector are doubble tubes so the second tube keeps the single tube from twisting.