Steve,
On each Background sheet in Draft where you want to see the watermark, place the required text etc. and assign a Style to control the size/appearance of the text. For example, you might want to use an outline font in a light grey. Don't forget to set the attributes of the watermark such that it is pushed 'behind' other Drafting entities otherwise it will make the drawing difficult to read by obscuring lines, hatching, dimensions etc.