OP, the "clipping" your noticing is bad latency. This isn't your fault, it's bad net code on SE's part. That said, even with 0 latency, the GCD is still going to be more significant in regards to a DPS loss. In other words, no matter how you slice it, do not weave Ruin II into your DoT application.

pandabearcat offered the best, and most coherant answer in this thread, so listen to her. Once you finish your initial rotation (pretty much everything she listed, in order), then we go to a priority system where you virtually just refresh what needs to be refreshed.