There's a setting to turn leds to a particular level when headlights are On:

So with v432, one can now specify the exact brightness level to be used whenever headlight sense is active (lights on):
[hijack] buttonled_dim=7
(full M Lord post explaining)

value must be from 1 to 7

Then, in hijack menu, you set the value when headlights are on to 0. Whenever they are on, leds will come at the level specified by the config.ini setting.

I'm doing this by memory, but I guess it is ok.