Herioc Spine for boomkins is not necessarily about the tendon damage you can put out, in my opinion. Other classes (mages/rogues/warriors/pallies) will/should be the top damage on the tendons.
My responsibilities for this fight are the following:
1.) Initial damage on corruption to break grip (try to keep this number to as little beyond 15% as possible)
2.) Innervating healers on CD
3.) Tranqing while amalg has 9 stacks during 1st time of being on the 3rd tendon.
4.) Lastly, damaging the tendon as much as I can.
I do exactly how you suggested, I reforged all of my gear to mastery, got Bottled Wishes, and I stay 1 starfire away from being in a Solar Eclipse. I then use moonfire/insect swarm on the amalgamation and spam wrath. This ensures that I will have a full Solar Eclipse and Nature's Grace for the tendon. Around 5 seconds before each Fiery Grip, I place 3 shrooms under the corruption and denote them as soon as fiery grip occurs (needs 15% damage to break). For our strat, we have all ranged do an initial cast on the corruption, then the spriests/arcane mages make the corruption to as little beyond as 15% as possible. This is crucial because you do not want to have an extra amalg spawning as your initial amalg is approaching 8% hp.
As the bloods start to increase, I have to be careful with using mushrooms on corruption because our kiter sometimes brings all of the bloods over the corruption as fiery grip is happening. In this case, precast a wrath ~1sec before fiery grip is going to happen.
As for during the actual burning tendon itself, I do not push mushrooms down near the tendon, I place them under the corruption (which should be at ~5% hp) that is about to cast fiery grip. Since denote is off CD, I don't waste a global and this helps with the damage to make sure the fiery grip does not happen during the burning tendon. Since the tendon is only up for 20 secs, I cast trees before I can even target the tendon to maximize that damage. As the tendon pops, I use Bottled Wishes, IS, Sunfire, Starsurge, Wrath spam until starsurge comes off CD (either geting and using an insta-starsurge immediately or the 10 secs (using 4pc)). I would strongly recommend you DoTing the tendon, the 2pc bonus is very nice and DoTs accounted for 26.5% of the damage on the tendon for me (seems too much to lose if you do not DoT). I always use trees on 1st of the 2 passes per tendon and the ONLY time I use starfall is at the very beginning because we kill all 4 corruptions (2 before flip, 2 after).
I am unsure as to your strat for the fight, but I am able to down the tendon in 2 passes all 3 times. First tendon, everyone uses their CDs and we have healers DPS as well. Second tendon, all DPS use their pots on 1st pass (make sure you pot before you can target the tendon to maximize the effectiveness of the potion). Third tendon, heroism is used.
Logs: http://www.worldoflogs.com/reports/4np6 ... target=229
Video (kiter PoV): http://www.youtube.com/watch?v=QNhCS27A ... B7Tt_JHD1M
For any further questions, you can easily contact on me on Kenny US-Aerie Peak.
Thanks and best of luck