In the tech brief Stan mention the chokes should have each 11,6k I assumed he was talking about reactance of the coil at 5 kHz so I found the coils should have 369mh which is very reasonable
Now I though a good way to design the required voltage to saturate the core will be to calculate for the flux at the core of choice accounting for the number of turns used and crossection of the core frequency ..
Stan clearly stated on the tech brief that the resistance of the coils is necessary to avoid unwanted oscillating currents that would distort the signal basically filtering some frequency and amplifying others...
THE z of the circuit determine along with voltage applied the maximum current the circuit will be able to have