What to do with a +RES -DEF Clair?

So, while hunting for Delthea on the DB banner, a wild Clair popped up and runied my pity rate. She's +RES -DEF, which is perfect for the mage tank set, but I don't have Berkut or Hector, so I'm forced to run an offesive build. I saw a fun budget build with Silver Lance+ and TA3 which I'm gonna shoot for.