I'm going to offer some suggestions that are gonna really help this deck out but it probably won't look the same way as when it was first conceived. Firstly you're gonna need more eldrazi that actually contribute to the whole of the deck. Creatures can make other creatures that can be sacrificed to make more mana. You're playing G/U so you should be playing cards like
retreat to kazandu,
sylvan scrying,
swell of growth,
seek the horizon, more of those hedron archives, and the other colorless creatures that have the devour effect.
Bane of bala ged,
desolation twins,
endless one,
titan's presence,
benthic infiltrator,
eldrazi skyspawner,
dispel,
mist intruder and
incubator drone and other blue (and even green creatures and spells that contribute to the deck). Think of it this way; If you were part of the Simic guild what kinds of spells and creatures would you use? Most likely creatures that grow fast and spells that help them grow even larger while still holding a tactical advantage over the enemy.