The notes for the log drums Billone asks for are very difficult to make and do not exist in factory-made log drums. You can try to make them yourself with well-resonating wood. I bought both the small and the large versions of the ready-made log drums from Kolberg (logdrum 1 and logdrum 2) , and asked for interesting intervals at the factory (I got E-C-C#-F#). They are quite pricy, but they have a smart stand and are quite light to travel with.
For the woodblock Billone asks for, I bought mine from Boris Müller, an excellent percussionist who builds excellent instruments. He makes woodblocks and slit drums in any tone you want. They are also quite pricy, but you have them for a lifetime if you treat them correctly. Other options are also possible, depending on your budget and taste.
It is best to mount the log drums and woodblock in a way that the edges of the different instruments are not “smooth” but a bit like a small stairway. In this way, when playing the glissandi Billone asks for, you get a resistance in the mallets, which makes the playing more articulate.
First of all make sure you have a practice set of mallets next to the mallets you plan to use for the concerts. The glissando style playing easily wears the mallets out, so it is advised to have a set of cheaper mallets to study the piece. Billone asks for four types of mallets.
I used one trap table at the low end of the marimba and used the part of the marimba that is not played through the piece as another trap table, covering it with a black cloth. Make sure your trap table has a soft cloth on top as well, so you have as few contact noises as possible. Also be certain that it is big enough to comfortably put all mallets except the hardest ones next to each other. Put the trap table in a sufficiently low position or sufficiently to the side, so it doesn’t block the view of the marimba. In some parts of the piece, where only the hands are used, I use the cords between the black keys of the marimba as an extra “trap table” when the playing area allows it.
When purchasing a normal Peking opera gong, you will find only two holes drilled in the instrument normally. It will be necessary to drill two more holes on the opposite side of the existing holes with a cobalt drill head to mount it properly. The gong is mounted with a normal marimba cord or similar cord; one side goes around the neck and the other side around the waist, mounting the gong on the chest. By bending over slightly, the gong will hang “freely” and can be played as if it were normally mounted on a stand.