Modifying HV supply for digital control
It's possible to get digital potentiometers. These are chips that have a digital control input (usually SPI or I2C) and act like a variable resistance or potentiometer (pot). Maybe you could replace VR1 with a digital pot, and control it from a microcontroller?

It might be a good idea to add some protection components around VR1, to prevent the high voltage from damaging the digital pot and/or microcontroller, in case of fault or accident (shorts or disconnections).