We're kinda similar in thought process then.
I pull with the tank for starters. This gives me enough time to move around Ravana and hit my first positional easily. I unload everything at the first, use my first GK, then if my groups burst is good, I save my second GK and burst them both during Prelude for the additional damage. I also just go x2 TTT during that cast.
For Liberation Casts, HT -> ID - > DIS -> TTT x2 + LS is the best thing to do and pop all my cooldowns, except BotD. Save it for the next phase. If timed correctly and if you have 2.39GCD (which you should with Deep-Fried Okeanis), you can land all of that in for highest PPS. I usually end this phase now, without a Ninja, at around 1.1k (I have my i190 spear now as well).
For the adds, I usually do my WT/FC's on him. I also do ID -> DIS on the spirits as it's the highest PPS to get them down, plus I can only get 2 GCDs max on them, then throw CT + cheeky PHs on Ravana (Got to paddle that damage)
For Pillars, I do something similar, I go HT -> ID -> DIS, no cooldowns, SSD/Elusive Jump back, then continue my burst rotation. I don't know if I should restart my combo from scratch or carry it on, as HT will always fall off for the last 4th doing it like this. Might try out different things, but I usually just restart it here.
Also for balls, something very risky. If you time it perfectly and attack straight as you get back to him, 30s into the phase, you should be putting DI/CT. Hold the GK just before he casts balls. Basically, the balls only explode once they tether. Until the tethers are up, you can walk through and around them with nothing happening. So I always position myself at maximum distance from Ravana and always get my last hit in when I see the balls, whilst positioning myself in between the balls. Once I see the tethers, I then go back to the wall, do the circle, then the second I see the tethers disappear, SSD/DFD, or run to ravana ASAP and finish off my combo, allowing me to keep BotD throughout this mechanic. You should have enough time during this to keep BotD up, as long as you landed the Disembowel and had at least 10s left on your duration. Kinda hard to explain, but easy to demonstrate.
EDIT: 3 gks in prelude? Woah. I need to fix up slightly then. I can only max out 2.
EDIT 2: Looks like my WD Formula is still consistent. Also, it looks like Skillspeed is scaling DoTs from 0. Recorded myself with 72WD, 827 STR, 373 DET. The slope or damage multiplier per skillspeed is 0.0192(rounded). Interestingly, 1/slope = 51, dead on.