Cage question!

[novanutcase]

I am trying to figure out how I want to configure the cage in my build and had a design question. I want to run the rear downbar inside the C-pillar('66 Chevy II/Nova) but if I do this it will hit right off the top of the minitub. If I welded tubing that was bent to the same outside radius of the tub and ran it from the trunk to the inside rear floor then welded the C-pillar down bar to it would this be structurally OK? I could weld a crossbar between the two radiused tubes underneath the package tray for lateral stability!