That would depend on what the other lengths of wood are supporting.I am in the prosses of putting a run on my shed the main 4 posts
are going to be made out of 4x4 but can the other lenghs of wood
be a smaller thickness to keep cost down
What size do you make each section
do you make them the width of the
welded mesh/hardware cloth with a
brace in the middle
Yes, at least. Hardware cloth here comes in rolls, so if that's what you are using, split the 20' up in to 5' sections using 10' long 2x boards for your top supports. If you are using welded wire panels, obviously put a support at each edge and then at the halfway point in the middle.