Not to discourage you, but I would advise leaving the craftwork to him. I’m not terribly familiar, but someone here linked to one of his songs where he was rhyming “very stable genius” with “tiny little pee-ni-us” and I realized I was witnessing the work of an absolute pro. Hell, not to discourage you further: submit what you’ve got and mention that you’ve hit a wall. Ask if he can add to it. Please provide a link if it becomes something!