We played with the Terrinoth magic rules for the first time today. The RAW specifically address how to spend threat generated when casting a spell. But our players had different interpretations of how to spend ADVANTAGE generated on a magic roll. One guy said that the rules only discuss soending threat so you cannot spend advantage during magic checks. The other guy says he believes that you should be able to spend advantage when casting spells because the Terrinoth rules don't specifically say you can't.
Then we also debated about using advantage to recover/cancel the two strain generated when casting a spell. For example, can you can't a spell, generate two strain, roll 2+ advantage and then recover the two strain of casting the spell?
We are house ruling that you CAN spend advantage but we are saying that you can only spend one advantage to recover strain incurred by casting a spell.
What do you all think?