Can you explain why Exploration is included? Except at low levels of life Fastbond is preferable. I would consider the following for those two slots:
Imperial Seal
Regrowth
Seal is an additional way to find Fastbond, or any other card you're interested in, and being a topdeck tutor has some synergy with Gush (i.e. make

and

from your duals, Seal up Fastbond, Gush returning duals. Play Fastbond, go off.) It's also an additional shuffle effect which is nice since your deck is running three Jace.
Regrowth has great general utility. It can recover a Nature's Claimed Fastbond, Ritual with Black Lotus, allow one more cast of Gush if you've found one, or recycle Time Walk.