About Gemini:
If I have fahrenheit in my hand, I play it immediately. Gemini normally won't start chaining shields for awhile, and in the meantime you do more than ~25 damage, or the damage one play of fahrenheit would do at the end. I've gotten Gemini down to 120 health before with it (it played a shield at 170 health, but that ran out and it didn't draw another for awhile).