I did not look at the manual to verify the height you suggest. But my 6 BVT is roughly inch and a half off the ground. I made my own radial attachment device it set's about the same distance off the ground. I also have my ground there and my static discharge on it. The Unun is located about 3 inches away on a fiberglass post. Only reason i used that was i had it in the junk pile. My actual ground system is a whole other story. But that's not important here as it most likely WAY over kill
But just used what i had and system works well.