Omega weapon is extremely easy IMO. All you need to do is get Zells str. very high. This can be done with STR. ups. Then cast doomtrain on Omega to weaken his defenses. Then do zells puch rush/booya trick. To do this all you need to do is simply keep on repeating Punch Rush and Booya again and again. If zells str is high enough you can easily do 4000 or more dmg (when I use it, it useally does 7000 dmg) to Omega. With this trick you can also easily land over 100 hit combos if you are fast enough. 4000 * 100 = 400,000 dmg! Do that 2 or three times and omega is dead. Combine that with Squalls lionheart and Irvines Fast ammo.