I have about 3.25" between the ground and the bottom of my tow poinst. I have bottomed out on them twice with a passenger. I do live in the mountains and the roads around here aren't exactly smooth or even. I'm OK with that.
I have yet to fabricate my tow bar. If I didn't have any plans for a tow bar, I would've made the tow/tie downs flat and had them stick out farther. I do use them as jack points though.
I did fabricate a spoiler that mounts to them, but I plowed my gravel driveway a couple of times with it, so I took it off. If I lived somewhere where I frequented highways, It might come into play, but it doesn't do any good on the twisty back roads that I drive on. I avoid 4 lane roads as much as I can.