Hey stink just stopping in to say hi, I have a answer about the paint, I would try Krylon Fusion is designed to stick to plastic. I have used it several times, with great results. I didn't use it on a grow system, but plastic in general. I always clean the surface with laquer thinner first, and then spray the fusion paint. Should work great. Hope its works for you.
Very nice harvest pics, your stuff always looks fantastic. I was at lowes yesterday looking into a roughneck for a close system. I checked out the other stuff to, but I think this grow is gonna be soil, I am however gonna get a cloner built from your plans. Thanks