Mujitsu and Tairaku's Shakuhachi BBQ

I find the keys without meri notes (Bb and Eb or A# and D#) to be the easiest. So for major scales that leaves C, G, D, and A. Since the cool part about most Western music is how it handles key changes, most Western music is way easier on a 7 hole shakuhachi. Not that it can't be done on a 5 hole flute, but until you can get the meri notes to be as almost as loud and as right on pitch as the non-meri notes the Western music isn't going to sound quite right, and to be realistic even the most highly skilled players will find, for example, 32nd note runs with meri notes scattered in there difficult. 

You might find Western pieces where the differences in shakuhachi individual note tone colors sound good. I find those very rewarding to discover. Often those are in Gm, and have both the meri notes. I absolutely love to find Western melodies that come alive on shakuhachi. It's challenging, sometimes you have to decide whether the reason a song you think might work isn't sounding good is just a matter of skill level or not. If you really like a particular melody a lot and can't see where it'll work even with a another year or so of shakuhachi practice, it's time to pick up pick up the 7 hole shakuhachi to play it... after exploring the same melody in different keys, that's good for both transposition skills and ear training.