It is always important to highlight that working with such a voltage level is not something for hobbyists, but for professionals once there exists the risk of serious injury. As for the circuit itself, for this specific application, what I have mostly seen is the voltage multiplier based on cascaded capacitor/diode arrays which is also the simplest option in my oppinion, but it must to be ensured that it will be completely discharged after use, in order to avoid to be a risk in handling the board even after a time.