FWIW topshelf did sell the black egg crate. They still may. Thats where i got mine. The black defiantly grows algae slower.
dont know what screw you need, but a mcmastercarr is a great source of all sorts off the shelf bits and peices. A bit more trouble, and cost when in jam micro plastics https://secure.microplastics.com has all sorts of plastic fasteners. they have distributors who sell smaller quantities.

no "smart ATO", but have a new in box JBJ Ato i can do for $50