I am leveling my BST to 37, it's currently 29. I have one tip for you.
Join a party.
BST is too hard low levels, you'll get better exp in parties and with less risk. Sure it's slower invites, but I've always gotten a party, with varied wait times.
But I'm different, I'm leveling BST for the sake of getting all jobs to atleast 37. I have no interest in actually playing BST. If you're playing BST for the thrill of soloing, then I'd suggest atleast leveling BST to 35 so you get Leave, then you can solo easier.