I have been using the Solfeggio set and have been amazed by the density I have felt in some areas with some of the tuning fork frequencies. You can literally feel where there is tension and I have been using the forks until I feel the tension melt away.
Here is an outline of what each of the forks are used for.
UT (ut quent laxis) Liberating Guilt & Fear … 396 Hz RE (resonare fibris)
Facilitating Change & Support … 417 Hz MI (mira gestorum)
Transformation & Miracles DNA Repair … 528 Hz FA (famuli tuorum)
Connecting & Relationships … 639 Hz SOL (solve polluti)
Awakening Intuition … 741 Hz LA (labili reatum)
Returning to Spirit … 852 Hz