I enjoyed this video on Tarot decks. http://www.youtube.com/watch?v=CcLDZzC-Zho&feature=related
I left this response if he approves it. I wanted to save it in case he doesn't.
I do have the Diva Tarot and I love the extra suit. I don't try to shuffle them. I make sure I have a big enough table, and then lay them all face down and swirl them around with both hands to mix them up (or I let the querent do it). One of my pet peeves with decks is when I can't see them in a semi-dark room. Most venues stick the reader at a table with candlelight or mood lighting. I'm tempted to add a head lamp as part of my kit. I do have one deck where there are 3 lovers cards (FF, MF, And MM) which is nice. I just can't remember which deck it is off the top of my head. I have about 70 decks I guess.