Very lazy!! ;-) Keep it as simple as possible, we did one for a global FMCG co a couple of years ago, nearly 100 pages & cost them nearly 20k, within a month of release the countries were ignoring it! very disheartening! Sizing - minimum type element not less than 5.5pt, colours - CMYK, PMS, RGB of core identity, possibly secondary support palette depending on design. Fonts…show alpha/numerical of chosen fonts - maybe look at web compatible for consistency across all formats..print/digital. Usage rules, put a clearance area around logo, don't tilt, angle, mess with design. Don't deviate from colours, show examples of key usage pieces…letterheads, vehicles, brochures, web, etc etc. Of course it all depends on the design at the end of the day…how complex do you make it? If it's nice and simple then so is the manual. Can be 100 pages or 3 (also depends on budget!)