WHM T13 Questions

[Lyrica_Ashtine]

P2 Giga after megaflare, what's good way to top this up? I find i either cast medica I early on in the giga cast to try to get everyone at max health for giga.

Keep an eye out on Bahamut's health. If it reaches to a point where transition is guaranteed after megaflare: Divine Seal -> Cure III the stack group -> stack up behind bahamut* -> Medica (don't wait for people to be stacked)
I do not recommend using Medica II before the adds appear for this phase. It's not really necessary and no need to go for that random off chance the tank can't establish enough enmity in a short time.

*assuming this is what your group does to prepare for gigaflare

Actual giga. What's the best way to deal with this? If i try to time a cure III as giga lands, i usually end up pulling instant aggro on the shadow that spawns, and get a quick meeting with the floor.

You can still time it without getting agro from the shadow. The timing would be when Bahamut finishes his fabulous pirouette spin (a full 360) for Cure III. Otherwise: Top your tanks first. Once hate has been established cast a Medica II from the center of the arena

Rage - Same kind of question actually.

For rage you can't do the same, sadly. The damage calculation occurs at the same time the add appears. Meaning that your healing can only take effect after the add is already there. So top off tanks again, run to the center and (swift cast) Medica II from there. The range should be enough to hit nearly everyone.

Additionally, what you could do:
When megaflare mechanics happen in phase 2:
Divine Seal when the first megaflare hits -> Cure III the marked group -> Medica after stacking -> Regen both tanks while Divine Seal is still up.
If you're also responsible for the main tank during megaflares, throw a cure or cure II at the tank first before casting Medica.

edit:
If you really need it, ask for a cover from the paladin. You can have it for: first and third ghost or only second ghost. Depends on whether your group is covering melees for earthshakers. Also applicable for the third phase.