Never tried a roast. I generally do london broils. Mustard & garlic rub, rosemary branches on the coals near the start; then move it back & let it smoke.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk