These are really a beautiful set of headers. Really nice job. Great welds.
I saw headers like this on the Holman-Moody Ford Mark IV continuation cars. They were not polished out. They had a nice golden tone to them.
As far as a support bracket remember that these headers move quite a bit when torquing the engine.
The supports will need to be flexible. I think this is why the GT40's use the "screen door" srings wrapped around the exhaust pipes?
I think if you don't do that you will stress the headers out at some point?
How close to equal lengths were you able to get the primaries?