Capillary matting is wonderful stuff!
I have five trays in a row. There is capillary matting running in a continuous piece along all of them.
The three middle trays are lifted up by a couple of centimetres and contain various Pings, pygmy Drosera, a Cephalotus and a Heliamphora. The outer trays contain other Drosera. The middle trays contain plants which I don't think want to be soaking in water, the outer trays have plants which are quite happy to be in water 2-3 cm deep. Don't know if I'm correct in my thinking, just going on experience and some stuff I've read.
The way it works is I fill the outer trays with water and the capillary matting takes the water to the three middle trays. Because the three middle trays are elevated the two end trays can be filled with water, but the three middle trays never have more than a couple of millimetres of water in. The plant pots sit on the capillary matting and draw up as much water as they need.
Seems to work really well. By which I mean, the Cephalotus and Heliamphora are both putting out new pitchers. I've kept a few of these in the tray system with 2-3cm of water and always managed to kill them. I'm much more hopeful this year, since starting to use capillary matting.
Plus the Pings are looking really good, too. So I'm hopeful this new (to me) technique will yield positive results in the long term.