I have never tried one but plan to in the near future. From things that I've read, if you don't cook them to a high temperature or sous vide for a long time, slice them very thin across grain.
I agree. The trick is to cook long and low temp to get both tender, and avoid dryness. I would agree with sous vide at 150 for 12-16 hrs (just a guess), and then put on the smoker at 225 with a pan of water, or apple juice, etc (if not I would inject it) and bring it to 203 or about. Alternative would be to smoke it at 225, (with pan of water) until it stalled and then put it into a foiled pan with beef consume (a cup or two) and into the oven at 225 until the internal temp 203 was reached.
We have a local restaurant that is famous for their roast beef. It is both lean, tender, and never cut more than 1/2 inch thick. I was able to find out that the cut is bottom round, but they would not tell me how they achieved the consistent tenderness and flavor. They always serve with thick brown gravy. Was able to find that they do cook "overnight"