Currently with the way things are coded, you can use wind-lore with an unimbued book to replace your -35% firelore with a -40% fire lore.

I made a short video about how best to utilize this and what happens if your -40% fire lore expires because you tried refreshing it with wind lore using your imbued book.
https://www.youtube.com/watch?v=3vG1CdMFyzo