Lived on the barrier islands for years and had snakes there too.
If you have never seen snakes in your yard, you are probably good to go. Just mentioned it because snakes really really upset iguanas.
I asked about the chicken mesh because I have read, on more than one occasion, of iguanas losing toes due to chicken wire.
You say it is "wire mesh". I hope that means a much thicker wire than chicken wire or you are going to continue to have toes injured or lost.
Why not just allow them to roam the entire screened in porch? You could put a shelving unit out there for them to sit on and watch the world go by.