Mulligans
General Mulligans
If you can get both Upgrade and Wrenchcalibur that's preferable, if not go for Clockwork Goblin, Wrenchcalibur, and Improve Morale to generate some nice little value pieces.
Aggro Mulligans
Get armor generation and heals, and clear boards fast.
Control Mulligans
No need to clear boards, just play bomb generators and go face.
Play your bomb generating cards, upgrade your Wrenchcaliburs, and then wreak havok with both booms summoning rushed mechs left and right. Clear threats with Shield Slam, Omega Devastator, or Improve Morale-Execute, 2 big threats with Supercollider, or bigger boards with Brawl or Warpath. Get plenty of late game value through Omega Assembly. And, if all goes well, at the end of the day your opponent has ~8 “Cast when drawn, deal 5 damage to your hero” bombs in their deck.