First rounds
Jayce Round
Board shown is stable enough to get you to the infamous Jayce round. At this stage you'll roll for your 3-stars. Blitzcrank > Ziggs. It's better to have a 3-star frontliner to buy some more time for ziggs to do damage. Luckily you'll be able to 3-star both Ziggs and Blitz using your 2 tiny dups. Don't be afraid of using the 2 dups on Blitz, and level up to have a better chance of winning the round. Ziggs will eventually will come to you.
For Itemization: I kept a 1 to 1 ratio, meaning, for each carry's item I'll build one tank item and viceversa
Position something like this
This way Jayce will focus your shitter vanguard.
If you get Shivanate this round, you could grief Jayce, making his 3 IEs turn into Shivs
Now start pushing levels and add more units
Flex other units but keep 5 honey + 2 vanguards
Depending on which frontliners you hit just play them, make sure to get Kench at some point since he'll be needed for later arcana.
Constantly change your positioning
Look where can you create a gap using Ziggs tech to snipe backline. For example, In Vex's round you'll notice that Vexes(?) are one hex off to the right, so create the gap opossite side so you can snipe the left side of the board. Also being creative to create gaps where there are frontliners on weird positions.
Vex example
Mord example
Mord round
First I can't remember how many Mords there are in this round, but the main idea is the same.
Clump everyone in the front-center of your board. This will make mini-mords spread to the sides of your frontline, leaving big-mord vulnerable with just one mini-mord in front of him, but these mini will NOT have the Zhonya's. He'll die instantly after Ziggs' first cast.
Keep on pushing levels as fast and agressive as you can aiming to 10 at 3-5 / 3-6
Get your 5-cost 3-starred
Now try to hit Xerath and some other random 5 cost (which is the golem).
Thanks to Ziggs you made it this far, now it is time for the big dudes to finish the game.