what are the best Manipulation Cards sold at penguin magic. one's that would be good for back palms and split fans.

Personally, I like these: http://www.penguinmagic.com/product.php?ID=S9935. They are good for backpalming. They say they aren't made for fanning, but when they are new, they can fan pretty well. I like them, but you will have to experiment with other company's cards to see which ones fit your style and hands best.
Drew

would they fan as well as regular bicycle playing cards?

Not as well as bicycle but if you keep good care of them, they will fan pretty well. It has a bit of a different feel when you fan since they are so thin, but if you practice, it will look pretty good.
Drew

I personally would just suggest to get some Bicycle cards (red backed as they blend better with one's hand), and simply work them. I'm personally not a fan of manipulation cards as they usually are bridge size, and I can get the same effect out of a worked pack of Bicycles.