Paddling in a dynamic environment, such as descibed here has many different layers to it. There is the boat, which is subject to forces of wind, waves and current. Then there is the paddler. Within that person, there is the physical component and the mental component. Put into a stressfull situation, the mental portion can have more of an impact on boat handling that one might think.
Chris, you mentioned that the boat may be too much boat for you. This suggests that you are unsure of your abilities at this point. I was there a short time ago myself. It also sounds like you were in conditions that you were not accostomed to. Speaking from experience, not having confidence and rough conditions will make the paddler tense and tend to over-react.
So how do we fix this? Learning boat control, especially on edge, in calm conditions is a good start. Learning to self rescue, or roll will also boost confidence and give you a firm understanding of where the limits of stability are, and how to react to them. For me was learning that the upper body and lower body work independently to achieve the same goal. Example, in heavy conditions, pressure on the foot braces can have a significant impact on the ability to steer the boat in the direction desired. Once you are gaining confidence in you boat control, start expanding your comfort zone by going out into more and more challenging conditions. Paddle with a group that is knowledgeable and willing to help you along. Having the safety net of good paddlers around you, will give you the ability to experiment and make mistakes, without getting into trouble.
Now to the question at hand about skegs. To me, a skeg is a tool at the paddlers disposal. It's not meant to fix any one particular characteristic of a kayak, but to work in concert with the boat, conditions and the paddler. Retractable skegs are particularly useful, as they can be dialed in to just the necessary amount to aid the paddler with boat control. I typically don't use them unless I have wind or waves that are causing too many corrective strokes in a particuar direction. In the rough stuff, I am not using the skeg at all. I want the boat to turn quickly, on command, and to not have to overcome the lateral resistance that the skeg would provide. In following seas, you will use your paddle, upper body position, knees and feet for boat control. In catching a wave, you will lean forward until the boat takes off. Once momentum is pushing you down the face of the wave, you will lean back to slow the boat down and stay on the wave. The boat is steered with a combination of a stern rudder stroke, edging and pressure on the pedals. If not catching a wave, waiting for the proper moment to correct course and staying loose is the key. Work with the waves to achieve what you want. Working against them makes for a very tiring day.
It takes a while to get to this point, and once it does, it's magic. Then you will be saying your Night Heron is the right boat for you. So if you want the flexibility of having another tool at your disposal, a skeg is a nice one to have.