Rear Frame Rails
I have used each of the methods to back half a car that you have mentioned and have also used 1 5/8 chrome moly and they have all worked equally well, because of extra bracing. The main thing that you need to do with any of them is to triangulate to make sure that the upper shock mount is solid and that the ladder bar/4-link mounts don't move forward or backward. I take the two bars from the top of the cage as far back as I can put them on the frame rails. Then I add the X-brace to the upper shock mount bar and back to the cage. I have tied in extra bars to the top of the 4-link brackets back to the floor at the main hoop and from the crossmember near the bottom brackets forward to the subframe connectors or the main frame. If you don't add these bars, I have seen the crossmember bend, the upper shock brackets flex, and these can cause safety and chassis tuning issues.
Good luck,
Bill M