Well first off you cant compare MP management of a SCH vs a WHM.
SCH simply cant run out of MP, ever. If they do, they are doing a horrible job at SCH.
They simply have way more MP management than a WHM.
That being said, Titan is an easy content that doesnt require your entire MP bar unless DPS is getting blasted by everything or the SCH is dying every 2 seconds.

Tips:

- Never use Medica 2 prior to breaking the heart.
- Always use Medica 2 followed by Medica 1s. (Medica 1 heals bigger chunk of HP, whereas Medica 2 heals more HP over time)
- Use Shrout of Saints on cooldown, always keep an eye on it and use it again.
- Use Virus + Eye for Eye on tank/Titan
- Use Cure 1 as primary, only use Cure 2 if it procs for a free cure or if Titan just used Landslide post heart to top off the tank. (Mountain Buster comes after every Landslide)
- Never use Cure on any DPS. This is the biggest mistakes of WHMs. Trow a Regen at them, if they are dumb enough to get hit again its not your fault they are retarded.
- Always prioritize your party as follows: Yourself > Tank > Second healer (if any) > Bards (if any) > the rest of the party.