you're better off creating a separate template for specific clients.
To make default font changes to the normal.dot, open the font dialog box in any document, make your change, then click the default button on the bottom left of the dialog box. Answer yes to the prompt to save Normal when you quit Word.
Only formatted AutoCorrect entries are stored in the normal.dot file. AutoText entries are also stored in the normal.dot file (unless you specifically choose to store them in other templates). To save these entries, be sure to answer yes to the prompt to save Normal when you quit Word.