To give a sense of what was/is possible with the version of Gotham City I came to believe in as a result of working with Matt Brady on the Daily Planet Guide to Gotham...I found a map of the outline of Manhattan Island, and scaled it to match that of Eliot Brown's map.

The Gotham Islands may be shorter on the north-south axis, but far wider on the east-west axis. So there's still room for at least twenty numbered avenues, and my research into references in both visuals and dialogue in comics published between 1983 and 2011 have explicitly referred to a 33rd Avenue (Robin v.4 # 162).
Numbered streets...might be more difficult to manage, given that north-south axis mileage. We have references of those ranging from 2nd Street("A Lonely Place of Dying", where it meets 2nd Avenue at Apollo Square) to 242nd (Batgirl v.3 # 6).
There's probably several ways for a competent cartographer or graphic designer to render all of that somewhat consistant.
Note - 2 Jan 2016: I will have to find new homes for a few graphics once I torch my LJ account. Like this one. Good thing my Flickr account is still active.