@excypher I believe in this case the shrink wrap modifier will be your friend. Duplicate your mesh like you did and sculpt your details in. Then shrink wrap your mesh with good topology around your sculpted mesh. This should preserve your nice edge flow and take on the detail you are looking for. Kent has a video detailing this workflow, I’ll link to it as soon as I find it.
EDIT: https://www.youtube.com/watch?v=MU7EQjauKNo
