I need help making individual body parts move for playing instruments.

I use the Motion Key Editor to set the hand location ,then I use the Body Puppeteering Panel to mask off the body parts I dont want to move and use mouse control to make movements.

This is a lot of trial and error because I have to find a motion that closely resemble the hand movement and the direction for mouse control of the hand on the instrument.

I was thinking ,there may be another or easier way someone can help me understand ,please.