how big are the holes on the mesh? they look about an inch big? It's hard to tell from the picture is the mesh on the inside or outside of the bars ? ( it looks like it's on the outside but I'm tired and don't want to assume)
Usually when meshing a cage we use hardware mesh with small square holes that are about a quarter inch. Anything larger than a half inch is to big. The mesh is put on the INSIDE to prevent the gliders from getting trapped between the bars ( with to big of a space between that they can get through) and the mesh.
I've seen people try to use chicken wire which looks about the same as what you are using but it's metal and had gliders get their heads stuck in it.
So if it were me, I would get a roll of hardware mesh for about 25 bucks, and install it on the INSIDE on each panel and bottom and top (roof).
Your zip ties look good and tight but i would put a ziptie about every inch to keep the mesh tight and no gaps that they can work on.