I was going to use two squares of aluminuim to attach to the shock towers with 2 lots of 10mm wide aluminium flat bar to bolt onto that (just to make them easier to remove) The 10mm bar would bend up over the cooling head to protect it. A brace across running just underneath the 10mm bars and attached to them would finish it off and make it stronger. Also where it joined to the shock towers and the body I would place O rings on the bolts between the parts to take some of the shock.

The rod you have may be a high carbon steel or hardened steel which is harder to work with ( it gains hardness but turns brittle). Also trying to weld copper to steel is virtually impossible.

If you have access to mig then why not get some flat bar, drill holes in it and weld them to the rollcage.

I think that makes sense??????