What stroke should I use and what adjustments would I make to most efficiently swim through rough ocean and breaking waves?
From personal experience, I tend to favor the breaststroke, over the freestyle/front crawl I would use almost everywhere else.
In choppy water, when doing freestyle, you can't really know if your rotation to draw air with your face low in the water isn't going to happen at the exact time a wave breaks over you. That would have you breathe in water or at least would interfere with your breath.
While less efficient, a breaststroke makes it easier to keep your head out of the water and be well aware of when you can time drawing in a breath.
Also, in breaking surf, the best way to avoid getting caught is to dive under the wave, which is easier to do starting from a breaststroke than a freestyle stance.
Long distance open water swimming, in calmer waters, has me back to freestyle.
It is important to be confortable with front crawl and to perfect one's dolphin skills (over and under waves).
I know people that walk or side-swim through the swells or whites. Assuming that the waves are big and near shore, swimming under them will help one save energy.
Apart from that, I would advise one to do a proper warm up and train regularly.
If one haven't swim in that sea before, consider trying to understand the currents and the way waves are breaking. One may be able to take advantage of the rip currents.