With consumer PWS most things are a compromise, but typically rain gauges are mounted at ground level with the top of the gauge about 1 to 1.5 feet above GL, temperature typically around 4-5 foot above GL, VP2 3-4 feet above ground level is a good compromise considering the combination. The anemometer at times will require servicing (cleaning) and replacing at some time and having the ISS separate from the same pole the anemometer is mounted also reduces any rain affect from the anemometer pole.