Red wing,
I think 50 Card decks do not have enough firepower to contend against strong defenses in 56 Card decks. Meaning, either you could devote several more slots to beef up your defense or increase your speed and soul generation so you can win before your opponent does. I know many other top t1 players will contend that the best decks are 50 or 51 cards if you use Haman's plot. However, I Usually shy away from making decks that small.
Josh,
That is fun to hear y'all used silver cup as well! I usually do not play games anymore but I imagine it would be effective.
Kirk