You'll want to buy some hand cards with "cotton cloth" on them -- extra fine, i.e. lots and lots of teeth, more than are on "wool handcards". I got lucky (lucky me) and bought Clemes & Clemes cotton handcards on eBay that were in like-new condition, 5 years ago. They are getting rarer now, given they aren't made any more. I like the curved backs -- not sure who does curved backs in new handcards these days.
I've heard some good things about teeth density on the Strauch hand cards (at 255 teeth per square inch). Some makers have "cotton" handcards but the teeth density isn't all that great.
BTW, cotton handcards are also great for carding angora! And BTW2, if you have bad wrists like me, the "child size" option, if there is one, is a good idea.
(posted by me this day on LJ:spinningfiber)