For the most part, my readings are at public events, where I am giving someone their first taste of tarot. There was a time I tried offering options on deck or spreads...and there was a unviversal confusion among my clients...who ,not knowing a thing about what I was doing, trusted me to make those decisions for them.
And I have come to rely on my own intuition to tell me when to choose a different deck from the norm, or throw the cards a different way than usual.
It just comes automatically now.
On the other hand,I know a fabulous oracle reader who reads from Doreen Virtue decks, and has the client choose one of four. She says some respond to messages differently if they are given by Goddesses, say...instead of Fairies. (Even though they may all give the same message!)