You have to meet all the other requirements to use the card, in order to get the effect. So, hand size would matter in the same way it does for playing Steven's advice.
== the old edit the question after the answer trick, eh? ==
Steven's Advice does not need to be included in your hand, in case that's what you're asking.
When you Telepass or Sharing for Steven's Advice, there can be no more than 6 cards in your hand. The ruling at the end of the HL version eratta still applies,
== STEVEN'S ADVICE (EX:Hidden Legends)
* Steven's Advice should read: "Draw a number of cards up to the number of your opponent's Pokémon in play. If you have 7 or more cards (including this one) in your hand, you can't play this card." This errata replaces text of "more than 7" with "7 or more". If a player has 7 cards in his or her hand (including Steven's Advice), they cannot play the card. (Oct 1, 2004 PUI Announcements)
