I do not actually think the goal of this game should be to make all games fair, the goal is to make the people build good decks, and if an opponents deck is better, then he just buildt it better! (if you do not have good enough scrolls your goal is to get new ones to improve your deck)
So if you add handicap, the reward of a player who build a good deck is taken away from him! I personally do not think this should be the way to go.
As for the "fairness" of scrolls: beginners should only battle beginners etc. so when you have a "bad" deck and dont have the scrolls at the moment to make it better, you just get matched to similar opponents (after a few losses maybe) and when you get the scrolls you needed for improvement, you will get to play against better opponents, a simple rating system should be the way to go in my opinion. (in addition to a beginner-lobby of course)
As for playing with friends, an experienced player can just give the beginner one of his decks for the time, or he could make a similar-power deck. For this purpose it might be okay to do some kind of that. maybe just a function that you can loan a deck without actually trading the scrolls away so that the other player may play with it just for that one match.
Im thinking of a button where you can play with a friend and "give" him a deck he might use just for this match (you dont actually give him the deck he just uses it) it would be similar to paper-cardgames. It would solve the problem with "guy wants to play with beginner-friend but he has no deck" and does not really create balancing issues! and I see no other situation where a handicap might be useful