Yes. When I fought Omega and Ultima Weapon in FFVIII without junctioning and with the crappiest weapons, I almost thought it would be impossible at first... but I still managed to beat them that way. And you, Necro, have also got past almost unbeatable bosses in your FFX challange... so this have to be possible. I really hope Tidal Wave won't be the horrible attack that makes Shinryuu impossible, like Seymours Firaga storm did in your FFX challange. But I'm sure that atleast Omega is possible... even though he may be even whorse than no-materia Ruby Weapon...

However... for now, I'll just finish the game to begin with. I'll need a lot of power leveling and job mastering before even thinking about taking on Omega and Shinryuu.