I can't download the workbook and therefore cannot tell what may or may not be causing the issue. Do you mind either attaching the workbook to this post, or enabling download permissions for the workbook on public?
Okay, I just edited the settings to allow that.
The trick is to put the viz in a Dashboard where you can control the layout size. If you publish only a worksheet, Tableau Public appears to use a default size that you do not control.
I changed the Dashboard size to 800x400 and that seemed to work.
Hope this helps!
That did it, thanks!