I was reading the following question as I have the same issue: FTP and Apache permission issues
The first solution, while not the accepted one, seems to be close to what I need. I've added both users to the same group and chown'd all files to that group, I haven't yet changed all file permissions to allow the group to write.
Given that apache is supposed to execute any uploaded files, does that means the permissions for the files should end up being 775? If so, does that mean I should set my FTP umask to be 002? What are the security implications (if any) of changing all files in my web directory from 755 to 775? I presume there are none as long as who is within the group is controlled anyway.