EDIT: Credit to Zerris who posted his partly-broken infinite solution, this is a version of that solution which I fixed up.
Tap Swamp, Swamp, Island, Oboro, City, Plains for 7
Play Evolving Wilds, sac for Island
The top three cards of your deck are Kiki-Jiki, Budoka Gardener, Shallow Grave
Skill Borrower uses Kiki to copy itself
Skill Borrower token uses Kiki to copy itself
Spin Top to put Budoka Gardener on top
Hold priority, token activates Budoka's ability, then:
Spin top, put Shallow Grave on top, tap top to draw Shallow Grave
Cast Shallow Grave, returning Nissa, searching up a Forest
Top cards of your deck are now Divining Top, Dimir Doppleganger, Restoration Angel, Kiki, Batterskull, Shattergang Brothers
Resolve Budoka, putting Forest into play, flipping the Borrower token and transforming Nissa
Plus Nissa to draw Top
Have the flipped token use Dimir Doppleganger to copy Sasaya, becoming Sasaya's Essence (zero mana floating)
Tap all lands for 16 G, 2W, 3U
Play Top, spin for Angel, tap Top to draw Angel
Cast Angel, blinking the nontoken Skill Borrower
Equip Skill Borrower with Lightning Greaves
Hold priority and have Skill Borrower spin top, then:
Spin top again, putting Kiki on top
Have nontoken Skill Borrower copy the token Skill Borrower
Resolve the top activation, putting Top back on top
Tap the Skill Borrower token to draw Top
Play Top
Spin Top to put Batterskull on top
Use Batterskull to return the nontoken Skill Borrower to your hand, then recast it
Spin Top to put Kiki on top
Equip Skill Borrower with Lightning Greaves
Use Kiki to have Skill Borrower copy a token Skill Borrower
Equip the token with Lightning Greaves (to make the nontoken Borrower lose shroud)
Have the token use Kiki to copy Restoration Angel, blinking the nontoken Skill Borrower
Repeat the above four steps to create infinite Restoration Angels
You now have infinite Angels, one untapped Skill Borrower, and your top cards are Kiki, Dimir Doopleganger, Batterskull, Shattergang Brothers
Make a Skill Borrower token
Tap top to draw Kiki
Hold priority, have Skill Borrower spin top, then:
Tap the Skill Borrower token to draw a card with Top (top cards are now Dimir, Batterskull, Shattergang)
Resolve the spinning top to put Shattergang on top
Sacrifice Sasaya's Essence to Shattergang to destroy Solitary Confinement
Attack with infinite angels for infinite damage
Old version, Turn 1, 15 damage:
Tap all lands except forests and plains (this gives exactly enough mana for now)
Play Evolving Wilds, sacrifice it to find Plains
The top three cards of your deck are Kiki-Jiki, Budoka Gardener, Shallow Grave
Borrow Kiki to copy Skill Borrower, repeat this step twenty times
Top to put Budoka on top
Hold priority and token Borrows Budoka, with that on the stack:
Top to put Shallow Grave on top, then draw it
Cast Shallow Grave to return Nissa
Use Nissa's trigger to put Forest into your hand
After shuffling, the top cards are Top, Dimir Doppleganger, Shattergang Brothers, Ghave
Resolve the Borrowed Budoka activation, putting Forest into play, flipping the token and transforming Nissa
Activate Nissa to draw Top
Have the flipped token Borrow Dimir Doppleganger to copy Sasaya, turning it into Sasaya's Essence
Tap four forests for sixteen and two plains for six (22 mana)
Play Top (21 mana)
Rearrange to put Shattergang on top (20 mana)
Activate Shattergang (17 mana)
Rearrange to put Ghave on top (16 mana)
Use Ghave to sacrifice a Skill Borrower token to put a counter on another Borrower (15 mana)
Remove the counter to make an untapped Saproling token (14 mana)
Sacrifice 14 more Skill Borrower tokens to put 14 counters on the Saproling
Equip the Saproling with Lightning Greaves and attack for 15.