Just curious, why the need for another thermometer? While they say it isn't the most accurate thermomter in the land, you have the lid temp on the WSM, The lid thermometer, along with your ET-732 should cover all youe bases. If you are looking for a back up, try several smokes with just the lid thermo. Find out how it cooks. You may even want to take it out, place it in a pot of water and bring the water to a boil. (This is the best way to see how accurate your Lid thermometer is.) This way if your batteries die, or you are without your Maverick, you will know where you stand with the lid temp.
Hope this helps,
Tim