Awesomeness... sweet... but back on topic.
3 HG's can work, however, regardlesss of statistics or a little pointless arguing, more than 3 HG's in a deck of 50 cards would be optimum, as Yaladilae says, for the simple reason that you have more chance of drawing an early HG if you have 5 in a 50 card deck than if you have only 3.
Further and to put it in simple terms, yes you can draw all 5 in your opening hand. Conversely with 3 its just as possible to draw 1 early, have it destroyed/stolen then wait another 40 cards before the next one appears... but if you had 2 more in your deck, you might draw another earlier!
Any newbies reading? Listen to Yaladilae & Puppychow, you know they make sense.