I only really looked at your best Chaos parse and I'll tell you that you seem to be doing it right for the most part. Use of heals, dot uptime, use of stacks, etc.. looks good enough to earn you purple parses. The one thing that jumps out like crazy is that you should be casting at least double the amount of broil II than you currently are and way fewer ruin II (noticed the same on midgar & omega). Like others have mentioned. Just keep ruin II for running and/or double weaving when miasma II or bio II make no sense.

This to me indicates some uptime issues and a lot of running around. Might be worth cleaning up some placements and getting into the habit of slide casting instead of just moving while throwing ruin II.