Does anyone uses Oracle to Heal Challenge Modes??
It should be similar to dungeon healing, but you would be crit / spirit crippled during the run.
Practise with pvp healing.
You should never really keep players topped up, but this is contrary to most healing thought processes. It will be more like pvp healing than raid/dungeon, and survival rather than topping up. Lots of absorbs.
Apart from spec and talent / metagem choices, which will be nerfed as well, tyrael should be healing out of combat, and using cooldown abilities more often due to speed/effect.
The problem with cm runs is the throughput is very stop/start when spirit is low. You require a continuous healing process and pvp healing /speed bursts are ideal.
I have run a few CMs not as healer, but as tank, and it is all about communication and trash pulls. Visible timers helps to learn when off track, or where to spend the time on moving trash to the boss or clearing before pulling. Mana is usually the first preference and projection of speed. Once the routine is in place, time is irrelevant, but not early on.
Disc or resto works well because you can apply HoTs on moving targets, disc can speed up the tank on pulling mobs while moving, and speed up the healer as well. Mist can also keep up with movement and chain pulls, but you should macro or hotkey abilities that use AoE with burst cooldowns.
The priority in CM is mana regen, movement and keeping AoE limited to stopping at large trash packs. And avoiding the urgency of hitting 100% on the group.
Don't use onBoss settings, and enable the low throughput spell usage so you can help mana regen. You just won't be able to chain pull trash unless the tank and DPS can CC well, or know what trash packs should be avoided.
The other problem will be DPS and CC usage, which is going to be very class specific, but if you want to aim for gold, you can't DPS, you have to avoid pulls or use speed/invis potions.
Tanks are the bottlenecks in CM modes, as well as training and cm experience. Switching between heal and CC might work, so you can use modified pvp settings rather than dungeon/scenario settings. Tanks and DPS have to know that the trash is more dangerous than the bosses, and that will be the first challenge, because most ignore trash performance early on in CM.
Video runs of CM gold runs should be used for comparison, reviews and training for combat awareness.
Oracle settings should be able to accommodate everything, but it requires being experienced with hotkey usage, or trusting the routine to handle mana and DPS / CC /burst/ CD usage. Also health levels.
Tweak the settings for difficult CM gold runs, and they should work for all other runs.