Filling the baskets is a bit nerdy and can take a while. I find that you want to use the bigger rocks on the outer edges. I start filling all the way around the edge and then back fill the middle with smaller rocks. This makes the walls really solid and less prone to getting misshaped by the weight.
You can see the inner chamber wire supports i thread through in the first two photo's here.
I fill the front (Joined to another basket) edge first and then try to have the next basket ready as i'm filling up the back building it's front connection together for best results.
I have 400 sq feet of rocks currently in these baskets around my front and back yard and living in a low humidity non coastal environment i imagine these will be here long after i'm gone.
So far it's only cost me $200 and my time... Oh and a few cuts and scratches.
I'll post the photos of the cage i built today being filled so you can see how i match the ends together.