I need to install some poles off my back porch to enable me to string up a sun sail. The sail manufacturer recommends using 4x4s, but that seems thick and ugly to me, so I was thinking about steel square stock or steel tubing. I had hoped to find some kind of equivalency table on the web, but no such luck. I'd rather go with something of a smaller OD and thicker wall than something thin walled with a thick OD.
Anyone care to venture a guess as to what might be comparable in strength to a 4x4? Square or round better?