Have you been reading the blogs, etc. on those?
The way I understand it, the bottom pockets get wetter due to all the moisture dripping down, so more moisture loving plants on the bottom, and upper pockets tend to dry out a lot faster due to greater exposure. The back of the organizer gets very moist and it's in advisable to actually hang them against a wall that you care about moisture damage unless you use a vapor barrier to protect the surface.
What kind of organizer did you get? I haven't tried yet because I got stuck when I started to think about cotton canvas ones which tend to have formaldehyde based sizing and sometimes non- flammable finish on them vs. polyester or nylon ones. Also, there is usually a cardboard stiffener inside which will most likely deteriorate due to moisture. Not all of them say what they are made of.
Also, at least one person said it would be better to cut drainage holes in corners of the pockets because hers didn't drain as well as she thought.
I haven't decided if I want to this because here, we have drought in the summer, and I don't have automatic watering system. I have an as yet incomplete idea to hook up a watering system from the rainbarrel to a vertical wall garden but the actual construction/structure is still up in the air. This was one of the design candidates. It's one of my back-burner projects.