With AP, you will want to be able to adjust two settings: maximum speed and minimum following time-distance. From the owner's manual: Pressing down once on the gear shift lever engages cruise control and sets the speed at your current speed. But then to change that speed you need to use the screen, as far as I can tell. (My Prius lets me increase or decrease speed on 1 mph increments by tapping the cc stalk up or down.) I have not found how you set the following distance with TACC.
On Page 61 there's a confusing section that says you can briefly accelerate to your set speed when using TACC by holding the turn signal stalk up or down. I already know (from my drive) that pressing the turn signal stalk up or down once causes the respective turn signal to flash three times (for changing lanes) and tapping it twice turns on the turn signal and keeps it blinking until you turn or disengage it. This additional function on the turn signal stalk seems like it could result in unexpected behavior if you accidentally give it the wrong signal.
Come on, Tesla, cc needs its own stalk!