What I anticipated being the main/alt setup is now reversed. My tank was on a weekday ToES run, my Rogue did this weekend's ToT run. Neither are a proper 3rd group, and both are in a state of flux. Uncertainty is present.
Anyway, onto the Horridon kill numbers:
My DPS continues to be low during the gate phases, jumping up from #6 to #3 during the end burn phase. I was intentionally not using cooldowns at all during the gates, since I was focused more on surviving. I'm the only DPS that has to worry about 110% threat threshold as opposed to the 130% threshold ranged gets. I die a lot, almost always to melee attacks. Sometimes from debuffs, but that hasn't been too much of a stumbling block for our group.
Tricks only can be used every 30 seconds, so I try to use it for sure on every pair of the high priority adds each gate, again on large packs. I hit Tricks and spam a few Fan of Knives ending with a Crimson Tempest. This actually drops my DPS since Fan of Knives is usually replacing Mutilate only when there are 4 or more adds and Crimson Tempest is not a part of any standard Assassin AoE rotation that I know of. I'm considering taking it off my bars and just sticking with Envenom. The goal instead is just to help establish threat on multiple targets. When I don't have Tricks up, I try to single target only the highest kill priority until dead, then spread 3-4 point Ruptures on adds that the tank has good threat on, then Marked for Death> Envenom on adds that are about to die.
Marked for Death is working out well, but it's best benefit isn't actually it's small but visible DPS increase. I observe that there are less stragglers to deal with after crashing a gate and moving to the next one. Killing off these lower priority adds has been an improvement for the whole group of course, but on my end of it, I think the extra 5 point Envenoms are exactly what's giving me the little bit of burst to contribute to that part of the fight.
Overall DPS on adds, however, is not improved greatly. All through the fight, my DPS is between 50k-60k DPS. It more than doubles during the burn phase, since I'm synching up cooldowns with good effect, so perhaps gate phase DPS can also be improved with judicious use of cooldowns. Typically one would want to burn the Dinomancers, but I'm actually on orb duty, so no burst there. I suppose hitting a cooldown on the pairs of adds would help, but still, survival is paramount.
Which leads me back to my initial problem: I die a lot, almost always to melee attacks. Every time I die, I think it may be decreasing the likelyhood healers will heal me. Raid healers prioritize, and people who die a lot tend to be seen as bad investments of mana, which is a finite source for them (tank healers, not so much). I use meters to gauge how healers respond to relatively higher damage taken by DPS players by comparing Damage Taken with Healing Taken. If the place on the list is within a position or two, no problem. Healers are responding proportionally to damage taken. If Damage Taken is much higher than Healing Taken, then there may be a problem.
In each of our attempts and in our kill, I was in the same relative place on both meters, and I am encouraged by this. This means that if I focus my efforts on what I can control, i.e. better burst DPS and better survivability, then what I can't control, i.e. healing received, will continue unabated.
There's still the uncertainty concerning scheduling and grouping to address, but that's something I have very little control over, and is too close to airing out laundry. I only hope that soon a group or two will settle into a steady routine. I don't care who leads, or which team gets my DK or Rogue. I just want to raid.