Does hand size matter with palming? Cause my hands can barely palm a card.
Yes and no. No, firstly, because anyone can palm a card, as proven by many legends past and present, no matter the hand size.
Yes, it matters, because, unfortunately, it does mean that you'll have to work a little harder to conceal it better, and work out what works for you.
Truth is, even if a card is sticking out of your hand, there are still ways to hide it from view - the Gambler's Cop is a prime example. The same is possible with the classic palm by holding your hands at the right angle.