Tanking and self-preservation ftw ;)
http://www.dbocom.com/skillcalc.php?...10023150312044.

Hows it look?

i may not no a lot about ultimate majins, but spinning attack for mighty majin is a must, it is basically their best attack, likewise for spinning flame breath. u can basically take on several mobs, and kill them with this one attack

also, as u want to tank, u may want to consider max out shield, however that means getting other buffs u may not want