I'm working up a separate wiki page to cover this (and I'll probably do the same with other subjects as well). I haven't linked it from the main wiki page yet as I still want to do some editing to reduce the verbosity, and of course solicit commentary from everyone else on the forums, but the idea will be to link all of the subpages from the main page once they're done, rather than trying to cram everything into one page. This allows for more room to go into detailed examples, hopefully eventually with pictures to go along with them (guess I need to dig out my camera and go photograph some highway signs!).
At any rate, feel free to check the page out as a "sneak preview"; I tried to incorporate the suggestions from this thread and to elaborate more on some specific examples to provide guidance, although some things will ultimately just be a judgement call. Incidentally, I'm fairly happy with how the TTS renders the ramp names on the few interchanges I've edited recently (N1/Malibongwe and N1/William Nicol), aside from the "North 1" issue (hopefully Waze will fix that some day, but they still haven't even fixed the recent St=Saint issue...). I think I still need to check the ramp signs on a few of the ramps (not available on Google Street View), but it doesn't seem like the "to ..." ramps are causing a problem with TTS.
