I don't understand about the "leaf loss" from overhead watering. All my annuals get watered in this manner and I have never encountered any leaf loss from overead watering. What kind of annuals are you growing that are affected this way?

Depending on the quality of the potting soil you are using and the size of the containers, letting the plants sit in a saucer of water could be quite detrimental to their health. It really encourages root rots. And annuals growing on containers will need routine fertilization to maximize flowering and productivity. I fertilize weekly with a half strength liquid fertilizer. And it gets applied to the top of the container, just the same as the containers get watered.