what metal for tcs xtrail chassis shock hoops

[RootBreaker]

Ok so my FOFF is coming along and now needs a but of unlifting.
I took the shocks off on the top and now the bottom links sit level. perfect...

so to that I can make my own mounts.. well try to... see how well I can do that...

so curious what type of metal is used, how thick to go?
I ask that as I know there is cold rolled, etc for types of metal as we have a local steel shop nearby where I can get what I need.
Then I am thinking of just simply making a rectangle for the socks to mount to and bolt that to the frame...