UPDATE -
Thanks again for the advice all. We went after dark tonight and it's looking good.
Gear used - Drione dust in a duster , Surefire Sidekick taped a couple of inches back from the muzzle.
Protective apparel - Carhartt pants over tall rubber boots, T shirt with long sleeve heavy cotton long sleeve over it, then a jacket. Leather gloves with the jacket cuff taped in place over the wrist. Stocking cap to cover my ears, ball cap, and a head net.
The porch light was on but not helpful, so I eased in and shined a bright light to make sure of my bearings. Backed off, then eased up with the duster. Light on (I know, some say they should not be used, but how the hell would I know where to spray since it was a few inches back in the bush?), then I eased the wand through the bush and started squeezing the hell out of the duster. After the initial cloud cleared a bit I could see them crawling around with the dust, so I put the nozzle in the hole and let fly some more until I could see dust coming out of the top of the nest.
Backed off, could see a few staggering around on the walk. Gave it a couple of minutes then took another look and no hornets around the nest.
Touching base with the homeowner tomorrow for status, and may go back for another dusting, then will pull it Monday for it's time in the deep freeze.
Slumlord, I wanted to try your cover and fog idea but the setting wasn't very friendly for it, but I'll keep it in mind for next time.
