I am redesigning my drip system. It mostly serves large scrubs and mature shade trees some which previously got most their water from lawn sprinklers which have now been removed. ( I am in the Calif. Central Valley where we are in extreme drought conditions). We are allowed to water with drip 2X per week. I mostly have 2 GPH drippers on my trees now, but am wondering if I should switch them out to a slower drip rate, say 1 or .5 GPH? I can water up to 16 hrs. Per day on my given days.