There is no way to control this "listening" angle dimension during creation. You can adjust it after the object is created by selecting the object and then selecting the angle to adjust its measurement.
Listening dimensions is the technical term for the little blue dimensions that appear as you start drawing a line in Revit. The bold entry is the one that Revit is 'listening' to the keyboard for. When it comes to angular dimensions, if you start drawing a line then hit TAB it basically ignores the Angular snap increments and shows you the exact angle at your cursor position (go Manage - Snaps to see the increments). Also, if you put an increment in the Angular dimension snap increments that is notdivisible into 360, Revit will basically ignore it.
Holding Shift will constrain you to either vertical or horizontal directions.
In AutoCAD, you can access either the angle or the length of a line when creating a new line. Sadly, Revit does not allow you to access the angle while creating a new line or wall - you can only enter a Length (as this is the bold listening dimension at creation time).
