The rule of thumb is to calibrate with the master volume set to 0dB and to adjust so the test tones measure 75dB. This sets the "reference level" (what movies are mixed at) to the 0dB setting for the 1070's volume.

You can set the master volume to something lower when calibrating, or you can calibrate 0dB to a different level (such as 65dB or 80dB), depending on your personal preferences.