In co-located collaboration, people use the space above the table for deictic gestures, and height is an important part of these gestures. However, when collaborators work at distributed tables, we know little about how to convey information about gesture height. A few visualizations have been proposed, but these have not been evaluated in detail. To better understand how remote embodiments can show gesture height, we developed several visualizations and evaluated them in three studies. First, we show that touch visualizations significantly improve people's accuracy in identifying the type and target of a gesture. Second, we show that visualizations of height above the table help to convey gesture qualities such as confidence, emphasis, and specificity. Third, we show that people quickly make use of height visualizations in realistic collaborative tasks, and that height-enhanced embodiments are strongly preferred. Our work illustrates several designs for effective visualization of height, and provides the first comprehensive evidence of the value of height information as a way to improve gestural communication in distributed tabletop groupware.