Hey, I don’t know if you’re still looking for help, but this is what I think could help.
This biggest problem that I notice is that your group is going 2/5/15 for what I assume to be farm content (you’re 10/10 heroic which is why I assume). Your healing in content that is not progression will typically be a little lower on due to our mastery, and also normally you want to have fewer healers on farm content, not more. One healer to four other dudes is the norm, like 2/3/9 or 2/5/18, on farm content you should be paring down a healer to squeeze more DPS out of the group.
However, for things that you can change, I’ve noticed that you have Crashing Waves and EoE talented and that Riptide is often your most used spell, but it’s not paying out into more Healing Waves/Surges. I would recommend considering switching to Ancestral Guidance + CBT and stepping up the Chain Heal use. Chain heal is really, really good, and with you at 50% crit chance it is even better since you’ll get roughly a quarter of the mana back each cast. To also kind of put things into perspective, your Riptides are healing, on average, ~500K at the cost of one global cool down. Your CHs are healing for ~1.4M every ~1.33 (repeating, of course) GCDs, meaning that HPS-wise CH will net you more HPS when you are gaining your Tidal Waves.
Also, I wouldn’t worry about trying to always be casting. Take this KJ fight for example,
Where I cast the least spells in the raid but am the highest healer. It’s progression, not farm though so things may end up being a little different for your case, but judiciously placed heals combined with anticipating and preparing for incoming damage using our large assortment of CDs will let you do a lot of healing for very little mana, meaning you’ll have more mana for chain heals. It mostly comes down to knowing the fights and knowing when each cooldown will have the greatest affect, like Healing Tide when Krosus is going to slam and follow it up with an orb of destruction. Lots of people at low health so our mastery can really kick in.
For stats you want to shoot for at least 100% mastery, and everyone will have a different comfort zone regarding haste/crit. Personally I like 30% crit and 10% haste, but I’m also lazy and cast CH too often so my build enables my bad habits. I would also give swapping the Elemental Reblalancers out for Roots of Shaladrasil (no bias, I swear) because they are heavily overstatted on secondary stats, having a third category absolutely free, and their healing really does add up, even on fights where you’re at full most of the time. It’s a boring legendary, but it’s free heals and amazing stats to boot.
I hope this wasn’t too rambling and helps somewhat.