It won't let me post an armory link, but here is my character name - Squishyness - Suramar (US).
Right now, I am sitting at 820 haste, and am gemmed to socket bonuses, with Reckless Ametrine in both orange and red sockets and Purified Dreadstone in blue sockets. However, it seems that the larger the ICC buff gets, the higher my overhealing gets. It was 30-35% range without a buff, but is now up to 60%ish, which clearly seems to say the entire ICC buff goes to overheal.
I have tried going to all 20 haste gems (using 1 Haste/SPI and 1 Reckless Ametrine to activate the meta) in the past and found it didn't really improve output, and it caused mana problems. If I switch to that gemming method again, I would be sitting at 1120 haste according to Rawr but would drop SP to around 3450 unbuffed. What I am thinking of doing is going to the 18/53/0 spec, dropping Serendipity since I use PoH so seldomly (except on Sindragosa, and even then it's because its a slow spell that stacks unchained slower, so I don't necessarily want Serendipity procs). I am thinking that going to that spec would also let me use Althor's Abacus instead of Purified Lunar Dust/the 245 Solace as my second trinket and increase output a bit more? For what it's worth the typical healing makeup for 25 man heroic ICC is 5-6 healers with 2 holy paladins, 1 disc priest, 1 holy priest, 1 shaman, 1 druid.
Any comments? Is it better to go for the shaman style of gemming or stick with a more balanced approach?