Hi,
did it with the dust, at night, didn't get many flying around. Lots of 'guards' at the entrance but they didn't fly. (it was cold)
I also covered the torch with red cellophane as an additional precaution, not sure if it was needed or not, - never tried it any other way.
Next morning - insect carnage, dead and wounded lying every where.
The nest was totally dead the next day.
cheers