I love a EgadEgad!
I have a 2018 Ford Transit High Roof. On a level surface, I measured the distance from the ground to the highest point on my van - the cellular booster antenna, and added 6" to that which came to 10ft 10in. I then used a label maker to place "Minimum clearance of Xft Yin" on the steering wheel, the radio, and the rearview mirror.
I've considered one of those radar thingy's. How the GiraffeG4 Protects RVs