Note: The tuning ratio can change significantly when you adjust the (Wave) Shape slider, so avoid using it if making a subtle alteration to the harmonic or inharmonic content of your sound.
Shape slider: Modulate the carrier waveform. This control and the FM slider interact as you adjust either, resulting in a range of tones with more or less harmonic/inharmonic content.
Mix slider: Crossfade (set the level relationships) between the modulator and carrier oscillators.
Download the guides:
Logic Pro User Guide: PDF
Logic Pro Effects: PDF