You are going to want to have around 3200hp or more as a WHM/SCH. This means some Darklight gear/etc. You may have to do some Ifrit/Garuda farming to get your item, on the plus side you get tomes for gear so it balances out. If at any point you found yourself struggling on Ifrit/Garuda you are not ready for Titan. If the rest of your gear is fairly solid and your Main stat is in the 400+ range you should have little issue as far as gear. But no amount of gear will make people good at dodging the mechanics of the fight, that just takes memorization and practice.