Billone writes for 2 Tibetan sounding bowls of about 10 cm diameter and 4,5 cm height. These can be purchased at Asian Sound Köln or Kolberg Percussion. Alternatively, you can find them in local tourist shops, although it will be quite hard to get the right proportions that work for the piece.
Billone asks for two Tibetan sounding bowls of about 10 cm diameter with a half-note difference in pitch around the notes B4 and C5. I started using the normal chromatic tuned series Asian Sound has standard in stock. This series, however, is usually not the thickest sounding bowls and tends to break or tear due to the heavy hitting and dragging in the piece. For this purpose, it is perhaps better to find two bowls of the non-tuned series that have a thicker edge. These bowls will be higher in pitch because of the mass of the metal. If you take a B4 in a thicker series of bowls, you won’t be able to hold the bowls anymore because the diameter will be significantly larger. However, the edges of these thicker bowls are much smoother than the ones mentioned above, so some of the playing techniques in the piece will be harder to play due to these smoother edges. It is a choice the player himself has to make: you choose for the longer-lasting option from the non-tuned thicker series, or perhaps you choose the more interesting normal chromatic series that are more versatile to play. Make sure you don’t order the instruments without hearing or seeing them. Go directly to your dealer to pick them.
Because of the numerous amount of pages and the impracticality of turning them in a performance while holding two bowls in your hands - I also think turning pages simply doesn’t fit at all in the music of Billone - I decided to play from my computer and to turn pages with a foot switch. This setup is quite easy to make: you load the pdf files of the score into a keynote program like Powerpoint or even Preview and then use a remote control to move through the score. If you prefer to play from a tablet screen there are programs in the app-stores that are designed to read music. The footswitch I used was the Airturn BT105-ATFS2x2-PB. Another big advantage of this working method is that you can easily project the score while you are playing. Like this, the audience can follow the page turns with you.