Alan
a question of understanding? You have pots with a gravel on the ground?
When you have this, you can not use capillary matting. The soil-mixture must reach to the ground of the pot. Without this you have no capillarity in the pot. The best plastic pots for this watersystem have not a flat ground. You need a pot with little feets, than the middle of the pot will pressed to the mat and the water can climb up.