i would just call it out as "decorative half timbering" and have additional drawings showing the detailing you want - exact shapes, measurements, etc of each elevation. later, shop drawings will be made: a drawing of each and every piece of half-timbering.
There is a book available for viewing online for free called "The Half-Timber House" by Allen Jackson, 1912, which might be a useful reference for you.

Thanks for the help This is a challenge

Holy cow. Looks kind of cool. More photos please!