You want the C2V, not the "basic" C2 if looking at the ClearStream antennas. WFAA in DFW requires the VHF version of the C2. Any of these antennas can use a J-mount, typically used for satellite dishes.
There is no hard and fast height rule, but, it is important that you select a site that allows the best "view" in the direction of your broadcast towers. Placing the antenna where it faces point-blank into a tree, your own or a neighbor's house, and the like would usually be a poor choice.