Sub-frame connectors... Please build them correctly!

i have used one by two rec tube .100 wall and ran it under the front and rear existing stub frames overlapping as far as reasonable before the turn up for the wheels. this is super easy to do, doesn't cause any clearance problems, traps torsion cross member in the assembly,(good thing), and creates a box with the floor structure. Doubtful that a 40 year old floor has any structure to contribute. would have tied floor into it if i had the car apart and was installing new floors. i feel that by overlapping onto the stub frames by nearly a foot or more contributes to the rigidity and allows for a large welding area . I tacked mine in place after fitting and had a freind do the welds. (about an hour)