I did one similar to #4 on my 35 Dodge sedan (sorry, no pictures and the car is long gone). I used 1/8" round bar stock. Even with that light bar stock, it was pretty heavy. Not sure where you would find affordable tubing that small. There is a lot of material being used there, figure each of those upright bars are 2' - 2 1/2' long, then around the outside edge, it adds up pretty quickly.

I'm thinking a simple shiny outside perimeter, with 8-10 shiny cross bars evenly spaced apart might look OK. A couple darkened vertical bars for extra support would be OK too, they would blend in with the radiator and you wouldn't see them (I guess I'm assuming your radiator will be painted black.) Gene