Onyx
I've seen two different teachers (Scion here on the forum being one of them) who has a hunt and peck method where you sort of charge a card with your question, shuffle it into the deck, and then you look for that card in the pack. Once you find it the 2-4 cards before it and 2-4 cards after your chosen card make up the reading.
I love this method of reading and it is now my main style for tarot reading for myself. So I am a little shocked that I haven't thought of using it for the oracle.
The three extra cards are fantastic and I love just knowing that they are in the deck. They have yet to actually show up in a reading. (Bound to happen now!) I have left them unnamed and they represent the wild factor in the reading. There are wild things that are Fae world that I think need to be left undefined, unstructured and ready for the spontaneous appearance. They are the chance for the Fae to touch a reading in such a way that eliminated all my structured, western studied approach to the cards. I see them a intuitive prompts that will come alive at the right time in a reading.
Now all that being said this conversation has peeked me on the idea of using them as significators in a reading. I am intrigued with the idea of having the querent choose from the three cards which one best represents themselves, their situation, or the problem they want the reading for at that moment. Then using the Scion method charging that card with the meanig and seek it out in the deck
Onyx.