Great to hear that you are getting "crazy sharp" edges already, you will only get better and quicker.
Course, Medium and Fine are all good to have and depending on the condition of the edge, will determine which stone you will need to start off. If the edge needs a complete re-profile, ie chipped or severely blunt, then depending on how bad, the Course or Medium is your starting point. If the edge is pretty good, but a little dull, then the Fine is all you should need.
You will find that if you keep your edges maintained by stropping after each use or session, the edge will remain very usable for quite some time. When the strop doesn't bring back the edge, then you might still be able to bring it back using the Fine India or Ark only.
Freehand sharpening is a great life skill and a whole lot of fun. It is also not so difficult to master, as you have proven, and doesn't require the latest and greatest stones to produce shaving sharp edges. The good old tried and proven Norton India is a fantastic starting point, throw in a good finishing stone between 1000 - 2000 grit and you are set for 95% of your requirements. I still firmly believe that the Norton India is the best stone to learn the art of sharpening, I feel there isn't a better learning stone that can produce excellent edges and provide lots of feedback whilst sharpening. It is only when you need to sharpen these modern "Super Steels" with a high Vanadium content that these rocks won't work, Diamond stones are required here. Certain food prep, like slicing sashimi or sushi rolls might require a finer grit, 8000 or higher to put a high polished edge, but I find this degree of refinement in an edge is unsuitable for general food prep. Finishing around 2000 grit is my sweet spot for Kitchen and EDC usage.
I only sharpen with my right hand and don't flip hands, have tried both ways and am just a little quicker with right only. As you are learning, give both ways a try. Would also suggest watching lots of You Tube videos, there is so many different ways to skin a cat, just work out which way is best for you. I tend to sharpen more in the Traditional Japanese way, as most my Kitchen cutlery is Japanese.
Well done mate, producing Crazy Sharp edges with a few simple tools is awesome, enjoy the journey.