A large part of my work is writing about and sharing the Vuo story. We believe there are all kinds of people who will embrace Vuo once they discover it’s out there. So, my efforts include helping create the Vuo website, writing press releases, submitting conference proposals and generally figuring out how to create excitement and how to spread the word about Vuo. I occasionally help out with Vuo e-mail support and I'm part of the think-tank called "Team Vuo."
I suspect there are several ways to do this. The key for me was being able to use the mouse coordinates to indicate a specific item in a grid. I used a table I created within the composition for listing the specific items, which are the positions in the list. You could alternately input a table using a Fetch Table node, and output whatever IDs you need for your lights.
I'm not familiar with Art-Net, but our example compositions show how to send and received Art-Net messages. (This node set is included in Vuo Pro. If not using Vuo Pro, then you would need another protocol to communicate with your equipment.)