I just made a map viz with custom geocoding:
http://public.tableausoftware.com/views/suburb/Sheet1
and the file is 3.1MB (ten times the size I expected).

That is a good 6% of the 50MB allowed.

My first thought is that when a Tableau makes a packaged workbook that uses a custom geocode file, all standard geocode options (built-in data rows) are included with it, this way if someone wanted to edit the workbook, they can do so, keeping the custom geocoding intact.

Maybe instead of packaging up the currently made geocode database, just include the csv files in the user specified custom geocode data folder, and when someone else or Tableau Public opens the .twbx, the custom geocode data is merged with the standard data, instead of putting the standard data in the packaged workbook.

Currently I see two options:
1. do not upload custom geocode workbooks.
2. find a way to get more storage space on Tableau Public
3. see if there is a way to include the custom geocode file, without packaging the standard geocode data as well.

Does anyone have any other options?