I used to use the Tropf Blumat system for dripping, it was excellent, maintaining perfect watering levels, using simple clay sensors that detect moisture levels in the medium and drip feed accordingly. Worth having a look, cheap, easy to set up, no moving parts, no electricity, but great results. There's no over or under watering.
I had 2 drippers per 20L airpot for 3 airpots and was very happy, but you can't tailor feeds for individual plants unless you hand water on top of the blumats, plus you cant move or rotate the plants easily. It's perfect for a single plant.
BTW.... if you use Drip Clean, you HAVE to use it from the start, NEVER mid way through a grow, as it will release the already built up nute in the medium and overdose the plants!!!!!!