You need 60 cards in the main...
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I would add three more land, to make it an even 24. 21 seems a tad to little. Seachrome coast seems the best bet. On a personal note I'm note the biggest fan of champ, it's not a spirt anyway, I would add maybe dungeon geists, it's really good and he's not a wallet buster (yet) haha. Other than that, good deck!
How does it do at FNM's?
you need more land, preferably g/w duels to help mana fixing. Even with birds and all your ramp, 17 is way to little. Maybe up t.o at least 20-21 township is great in W/g too. Get that SB going too. Thrun would be good for any type of mirroish match too. Good deck idea!