R1 and C1 determine the oscillation frequency, different types of coils perform differently at frequencies changes.
I used 5v input and toroid ferrite, the output exceed 60v (no load). The output voltage will drop as the load go higher.
Other types of oscillators can be used:
Other one to use see here: Simple rectangular oscillator
7812 or 7805 regulators can be used to stabilize the output voltage. (remember not to exceed the maximum input voltage)