Need somebody to rap on the back half of a song (feature, royalties)

I have one song in a soundtrack for a book which requires a defter touch with the vocals than I have, and maybe (maaaybe) an alteration to the flow where required. I'm offering a third royalties on the song, whenever it goes up on streaming platforms and such. This is probably for a pretty niche audience (as I said, a soundtrack for a book) so I don't expect to shatter streaming records or anything.

Let me know if you want to hear it, here or in DMs. Thank you.