My heroes are all 9/10. Mino is 8/8 WG.
Looked through a lot of online stuff. Tried many many different drops.
Am I missing something?
It's hard to say why without seeing what heros you are using. Just having 8/8 WG Mino is not enough.
If you are stacking on the SK, check your pets. You DO NOT want to use Celestin. It will remove SKs proc, and you will kill the SK prematurely.