How might I have Webforms save files to private file system or as a database blob?
Did a little digging into Webform. There is a setting for this in webform I believe. There was an issue posted in the webform issues but it has been resolved. Saving file submission to private directory 

OP already solved but for future onlookers: There are instructions I believe on how to accomplish this in the comments of the issue referenced above, also make sure Webform is up-to-date.