I have been working on redoing the CODA system for a generic fantasy system, but here is a part of what I have been doing.
This is the magic system that I will be using. This is very much an early draft and is still a WIP. I have the system pretty much laid out, but am starting to work on the spells themselves.
I would love to have any feedback on this. I have used it with the LOTR magic, and what I did there is to say that the Manna cost of a spell is equal to the TN/5 of the spell in the LOTR book.
Don't forget the CRB as it incorporates the Weariness mechanic and provides suggestions for playing with more magical worlds along with accommodating "holy" magic as well.