You're missing the info. Go to www.dishpointer.com, enter your ZIP code and in the lower selector scroll near the bottom and select the Directv SL3. In the lower right of the map/picture you'll see the azimuth, elevation and skew. Skew is the tilt setting you seek.
You could also use the Zip code settings in the dish set up. I'm sure you know which zip codes you will be visiting. Before you set out on your trip, Go into Repeat dish set up and enter your various zip codes and note the values. They are starting points, guides to helping you find your sats before you fine tune.