Right there with you
I use a Suunto Tandem Inclinometer
They are great until you leave it at home or at the last customer's home,
Try........if you know straight up = 90 degrees and straight out = 0 degrees then half way between the two is 45 degrees. Compare that to the el for your zip. This gets you close enough to clear trees & buildings. Do the az from a nearby house or map (or a compass) and you can decide how much closer to measure. You know az, el & tilt from working in the area.