Rainbows in the Lehigh Valley Gorge

[ngauger]

Great work!! 

Sign making guidelines to think about:
-- The size of the sign matters as far as the cost to make it.  Signs are normally "only as large as they need to be"
-- The sign must be made and mounted to withstand rain, downpours, snow and wind
-- The supports must be able to hold the sign against heavy winds, hurricanes?

This is why the "painted walls" signs were made.  It was way easer and cheaper to paint bricks, than custom creating a sign.
Based on the size of the sign, the supports you have are a decent size for wind protection.

Now, with all that said; 2 options:
1 -- paint the supports in gloss black. They will look like (hollow) square steel tubing.
2 -- sand them thinner, by rubbing them on a flat piece of 200 or 300 grit paper to look like thinner square steel tubing.