There are no Stupid questions regarding Steem. It is a complex ecosystem where we can always learn something new.
At the moment there's no way to delegate only downvote vests but my best guess is that this is something the Steemit inc team might want to look into in the future.
Thanks for the interest though, have a great weekend!
Thank you for your reply. I really like curating but think that others would do much better work with more downvote power.