|1 person marked this as FAQ candidate.|
It works, you just have to take a second to state how you use it.
You can activate/deactivate the Ring as a free action at will, so you can do it just fine by deactivating it to cast your spell then activating it again before the end of your turn.
Yes you can do that, but you wouldn't get the shield bonus during your turn. I thought the OP wanted to get the shield bonus during Spell Combat. I might have read too much into the question.
Why not just use the Shield spell and a pocket full of Pearls of Power?
As people have already said, you can not use Spell Combat while using the ring, since it is "wielded by the wearer as if it were a heavy shield". You could switch it on in any round you aren't doing Spell Combat.
I would rather have 8 pearls of power.