I was always told growing up which I pretty much did at a nursery (grow up)Water in the morning early as early as possible try to avoid leaves or needles as much as possible . One problem we had in the nursery was iron in the water turned orange did not color did not hurt plant to much but made them hard to sell .As far as space goes I would say 15 to 25 feet I would also suggest staggered if you are using for a screen .
