Use this website to determine what your dps is and how much you are improving for SSS.
http://ffxiv.2digitalgames.de/
This is false, you do not lose your roulette bonus by running in a premade. The only thing you lose by entering the queue in any sized group is the "Adventurer in Need" bonus. There are plenty of people who run their roulettes in full premades just because they don't want to deal with the randomness of player skill that is the DF.
I question this statement because looking at your lodestone, your level of knowledge for the BLM job is in question due to how you chose to gear yourself and which materia you decided to slot. My guess would be that you are around i221-i223, but your stats are as follows:
SS: 787
Crit: 782
Det: 442
Accuracy: 672
As an i220+ BLM who claims to know the job, your spell speed is abysmally low. Part of knowing the job is also how to gear that job and which stats to prioritize. I also mentioned how you chose which materia to slot because you put determination materia into your Hailstorm rod instead of putting Spell Speed materia in there. As an example to an alternate choice of gearing, I play BLM as a main as well and we have a similar ilvl (I'm i223 now) and my stats are as follows:
SS: 1042
Crit: 875
Det: 307
Accuracy: 614
Both of us have way too much accuracy for the content we are currently doing (last 2 values for ranged that I have seen for A8S is 595 and 604) and since neither of us are currently running Midas Savage, we both have more accuracy than is needed.
P.S. I'm not questioning your ability to perform the rotations, just your knowledge about the job with regards to what stats you should be prioritizing over others. I only bring this up because I agree with the arguments about ilvl not determining player skill. To me, it appears that you are focused on ilvl rather than gearing properly.