Donphan

Prestiger vs Rhydon and Tyranitar if you're going to keep it at twenty. The defenders would have to be pretty high up there tho to be effective. Not getting 1000 out of a Rhydon

I have the same with 98%, and I would really love to have a Donphan as defender because he is so cool looking (and has reasonable CP).

But I haven't powered mine up yet:
Play Rough seems just better in every aspect on defense, considering most people will attack with Water mons.