Looks like standard DJ type tree lights. At best, you will likely only get a face light wash out of them. Not sure the spread on the instruments will blend enough to cover even a 16x16 space. It would be common to place them on a 45 degree angle downstage of the stage, with the trees at full height... keeps them a bit out of the audience's sight lines. You should check that they are outdoor rated first. Not all fixtures (especially those dimmer packs) should be used outdoors.