Well the significance behind zada isn't to carry the deck but to enhance it. Because you have so many tokens targeting zada ONCE will give ALL your creatures the same ability. So lets try this instead; If a card is MANDATORY for your deck run 4x cpoies. If the card is a PIECE or COMPONENT of a combo then run 3x or 2x copies depending on the mana cost and the role it plays. If the card is simply a stand in (or you can't get enough copies but it still works with the deck) then either run 1x copy or non. Also you have to look at the overall mechanic of your deck. If you're going to focus heavily on the tokens then the
impact tremors would be MANDATORY for this deck. Also adding
titan's strength is a good low drop way to scry through your deck including
bolt of keranos. If you play those cards with
guttersnipe on the field then you can
deal damage AND go through your deck faster.