I have an existing system installed years ago when the plantings were nursery stock size, now they are 18"-24". My 12" high heads don't reach over most of these plantings now. Do I install a 12" nipple under the head and support with a piece of rebar and wire ties or is there something else on the market? This area is in a shaded woodland setting in the back of the house, not in public view, as in front yard. Would you use a smaller head and longer nipple for less weight(this head is a roter)?