First, enable Boil Power Mode on your G30: hold the heat button for 6 seconds (holding it again for 6 seconds exits the mode). Once active, the LCD switches to showing just the current temperature and power output, and you can adjust the power in 5% increments using the up/down buttons.
For distilling, this is useful because lowering the power output slows the rate at which distillate comes out. This is handy during the spirit run when you're making cuts to separate the heads and tails from the hearts.
In practice, set the G30 to boil first, then switch into Boil Power Mode. Around 80% power tends to be the sweet spot for distilling, but feel free to nudge it up or down depending on how fast or slow you want the run to go.
Note: If you increase the power, you will need more cold water, as you want to ensure you keep the temp probe within the temperature range for distilling.