Default Folder Permissions

what you can do is use the setgid bit. man chmod.

just as an example:

find ./public_html -type d -exec chgrp www-data {} \;

find ./public_html -type d -exec chmod g+ws {} \;

I'm not sure what group you want to set.

Instead of cp, you could scp them to localhost:/targetdir as the target user eliminating the step to change their ownership.

I'm not sure if that's what you're asking for.