Final Final Fanatsy III Party?

So I’m just about to enter the Eureka and the Crystal Tower in the final stages of FF III, and I need ideas of a good party to use. I’ve played through most of the game so far with a Dragoon, Monk/Black Knight, White Mage and a Geomancer. So far the Geomancer is my favorite all-around class. I’ve looked a the final jobs, and I think the Summoner and Black Belt look like good choices, but what classes do I drop for them? Should I keep my White Mage and make it a Devout? Is it worth it to have a Knight, or train Bard this late in the game? Also, what level/HP amount should I work towards before I attempt the Crystal Tower?