If you were to choose once weekly feedings the only kind of harm that comes immediately to mind would be increased nutrient load caused by uneaten, decaying feed. Will you be able to make observations as to how much utilization you're getting? Fish are harder to train with an irregular feeding schedule, but I'd think that once they catch on, even less frequent feedings can be beneficial. Also lower frequency means that fish won't become entirely dependent on feed which can be a good thing as well.
