of course, they dont will ever be "farmed". I use two Tethys because even if I get her at my first hand, I still have the other copy in my deck.
If you started the duel, pass your turn, and do the combo next turn (it works mostly at blue eyes cup). If you dont started the duel, my condolences but you will need some luck hehehe. by the way, at the blue eyes cup, i dont lose for anyone with this dec