I was under the impression that unchecking "Change history" in table preferences would reduce the file size of the table. However, after some limited testing, it seems like it only hides the "History" tab. Am I right?
If yo uncheck "Change history" it means only that the tab will not be shown anymore in the form.
To reduce the size of your database you can delete the History in the database options.
Kind regards, Jörg