Understood 
I would suggest improving the readability of the code first in your current program. Think about places where using functions (like your MIDI_TX) helps by hiding some of the detail.
Then, read up about arrays in the tutorials on this website, and make sure you understand the examples. For practice, try to change your current program to use arrays, even though you only have two sensors and it may seem over the top. Better to start with a small example.
All the best
Ray