Ok even through I really think you should better write something like this here. I am willingly to answer your request here. Maybe I am not the right person to do this but just let us getting started ok? Please, while you read the following remember that I don not want to hurt neither you nor your guild members feelings on purpose!
Items and Stats
Where should I start? Your stats and your items. I would recommend you to replace your Horn of Cenarius with an Int+ second stat or the two most useful trinkets on top.: Heightened Senses and Vial of Nightmare Fog. I got the Horn with iLvl 880 and I only kept it for the group finder. Mastery may be our greatest stat but the active is too weak to justify it if you compare it to other, way more useful items. To see that you have got Nobundo’s Redemption makes me smile a bit. Many may consider this a bad item but I think it is most valuable in exhaustive fights and if you learn to use it you wont see any mana problems in future. All in all your stats are fine for your iLvl.
Torrent : Performs well in raids but Undulation and Unleash Life are formidable choices to maintain big single-target heals and they work far better with Cloudburst Totem or Ascendance
Deluge : Totally fine as long as you use your healing rain. For some encounters it may be good to change it with Ancestral Guidance.
Ancestral Vigor : One of the most controversial skills we have. Many think that the Earthen Shield Totem is far more useful. Try it out!
Cloudburst Totem : Is hard to master but it can be your most used tactic skill in nearly every fight. Look up the chainheal.com guides! Interchange able with Echo of the Elements.
Ascendance : Is total vale able but needs proper positioning and a bunch of experience with encounter tactics. Learn to time it with Cloudburst Totem. You can change it with High Tide to maximize the effect of your legendary.
Teaming and Raidsetup
I have taken some of your most current logs under contemplation and perhaps you can clarify something for me. Why do you need five healers for Ursco-HC? Not even one of you leaves with less than 30% overheal. Even if you would cut your guilds top healer Kishun you would create at least the ~10% overheal for the remaining healers. Palas make our lives hard enough but (!) keep in mind that Holy-Prists can burst their heal much faster than we do. To give something in return you can judge my logs as well and maybe you can take something from them for you or your guild.
Things you can do while you have some in-raid-freetime
Deal some damage. Make use of the mana-free Lightning Bolt!
Use of your items such as Cocoon of Enforced Solitude to regain mana.
Keep track of the encounter mechanics and use your knowledge to place your Spells such as healing rain or Gift of the Queen most efficient to maintain both; stable background heal and your mana stability.
Skill ussage and movement
Do not look at your damage meter during a fight! You don’t need to heal fast and dirty at the start of an encounter. Let the others take care of it. Should the dudu HoT them to death or let the Pala produce 9000% overheal with a criting flash of light. We heal most efficient in critical situations. Our mastery serves us best if our target is nearly dying. Don’t heal because you wan’t create high numbers in the rankings.
Use and take your time in point of movement.