TM, I'm sorry you are experiencing these episodic rages with Duckie. I would add these points:
First, from your posts, I'm getting the sense that the episodes are coming a bit more frequently. I think you should keep a log of behaviors, length of rages, triggers, etc. In the event you seek professional help later on, it's important that you have a record of what's been going on with Duckie.
Second, even though my kids no longer rage, they see a therapist weekly to work on coping skills. It helps regulate their emotions and gives them a safe place to talk about their feelings. I think it helps prevent meltdowns. Just because Duckie doesn't rage regularly doesn't mean that she wouldn't benefit from regular therapy.
Third, moms who parent challenging children need a safe place to explore their feelings about their children. You might benefit from either a support group or therapy of your own so you will feel better about parenting Duckie. This kind of intensive parenting is not for the faint of heart. Because my children can evoke very intense feelings in me, I've been seeing a therapist since the spring, and I have to say it has helped me feel stronger about myself.
Hug, TM.