Lots of folks have complained about Jiva so I decided to weigh in after balancing the zone.
I just balanced Sol Ro Tower with a level 65 Monk.
Monk had 100aa (dps), mostly ldon gear + some PoP gear picked up along the way while balancing tiers 1 - 3.
I actually play balancing characters to win (hotkeys, discs, potions, etc.).
Jiva went down first attempt.
My strat was to burn Jiva down (still took a while) while tanking all the adds.
Second attempt went just as well, but a bit faster because Jiva dropped the monk staff on first attempt and it was a big upgrade for the balance char.
The only thing about Jiva I changed was to make all the adds depop when Jiva dies (because it takes forever to kill Jiva + adds, and it's too boring). So if you kill Jiva, you win.
I consider Jiva well balanced at this point, but feel free to add any feedback here.
Flags from solrotower mini bosses (Jiva, etc.) are required to reach Solusek, Rallos flag is not required.
Jiva is a lot tougher than the other Minis, and Solusek is a lot tougher than Jiva. Good luck!