Hello Everyone, this is my first post here at the Mana Drain.  I've been following this Doomsday topic and now am planning on playing it this Sun at a local tournament.  What I have been wanting to know is what would be a good sideboard and which cards to take out for sideboard.  The main is really tight, so I'm having trouble deciding what should come out so that I can add my sideboard card.  I would say my meta here is lots of fishy decks 50% (TMWA, SSS, WU fish, etc) with some Ichorid 10%, Grim long 10%, Stax 10%, Gifts 20%... although now that gifts is restricted, I have a feeling these players will be looking to play Flash/Rector, Bomberman, or Grow A Tog.  Here is what my deck looks like currently.

// Lands
    2 Flooded Strand
    4 Polluted Delta
    4 Underground Sea
    1 Swamp
    3 Island

// Creatures
    4 Street Wraith

// Spells
    1 Mox Sapphire
    1 Mox Jet
    1 Black Lotus
    1 Lotus Petal
    1 Lion's Eye Diamond
    4 Dark Ritual
    2 Cabal Ritual
    4 Doomsday
    1 Necropotence
    1 Yawgmoth's Will
    1 Chain of Vapor
    2 Gush
    1 Ancestral Recall
    1 Time Walk
    1 Mind's Desire
    1 Mystical Tutor
    4 Force of Will
    4 Brainstorm
    1 Vampiric Tutor
    1 Demonic Tutor
    1 Imperial Seal
    1 Tendrils of Agony
    1 Research/Development
    4 Duress
    2 Unmask

// Sideboard
SB: 2 Darkblast
SB: 3 Massacre
SB: 1 Tendrils of Agony
SB: 1 Research/Development
SB: 4 Leyline of the Void
SB: 2 Defense Grid
SB: 1 E Truth
SB: 1 Sins of the Past

So, the question again is what do I take out for which cards against which deck.

I'm thinking about siding in at least 4 Leyline of the Void for 4 Street Wraiths in match ups: Bomberman, Tog, Flash, and Ichorid

For the Fish match, cut 4 Street Wraiths for Combonation of darkblast and massacre depending on their use of Plains.

Other than that, I don't know what I could do to make it better... I'm taking suggestions...