Hey can't wait to see this tank. Sound like you have pretty much everything worked out.
As for the lighting... 20W over a 30g is very low light. That's like .67W/g. I don't know what you can grow in there except java moss, java fern, and other plants of that nature. If you have Crypt Lutea then I'm pretty sure those are moderate light.
But I'm not an expert so anyone who needs to correct me feel free.