Try and get a Tee Jet Catalog, It has all the Height and width spec for their nozzles. From what you are saying I would adjust my height by eye ball then test it on a solid street or surface. That way you can watch the distribution of your spray pattern. If you get even drying on the solid surface you are Good. If not time to adjust. Remember many nozzles are made to Overlap. I have marked off 350 ft on my street. Up and back is 7.000 sq ft @ 10 ft wide. Any adjustments etc I make, I retest on the street with straight water. I changed the Engine governor to first tweak the speed to a constant 4 MPH. By having a constant speed I have a starting point to design pump and nozzles sizes. I like to over build and use the Pressure Regulator for the final tweaking. .