I go simple for top round. Salt, pepper, Montreal Seasoning. Are you doing a roast, or a London Broil. For London Broil, I do a reverse sear, bringing it up to 95 or 100 at 325, then get her rolling and finish with a sear for three or four minutes per side. For a roast, I actually do it at around 250 until it hits 135. I also rest my roasts overnight in the fridge, slice very thin (I have a cheap slicer) and then either serve cold, or quickly reheat in some hot beef stock.