[htp]

Now that I’m thinking about it:

What if you put one finger down to activate the interface, and tap with another finger (while still holding the first one on the display) to cycle through the menu?

This requires at least two fingers, but would allow for control of more settings, and would’t require you to remember how far apart your fingers need to be to get access to a control. You could have the car dictate the currently selected / active setting as you cycled through.