Kai, you seem to already know a good deal about boats and
boating and yes sailing is a little different. Size to
single hand depends on the set up of the boat and the
experience of the sailor. 60’ ocean racers are single handed by very experienced sailors. I’ve heard of 120’ schooners being sailed solo. More important is for you to learn to sail and to handle a sailboat. Before trying to choose a boat or a size get as much
experience as you can. Many people, including me, advise starting with a small simple sailboat (12-14 ft day sailor). Take a few lessons or spend time on a small sailboat (18-26’)with an experienced sailor. I don’t mean to be too specific about the boat size or type just the idea of starting small so you can feel the effects of
wind, weight, sail shape, etc. Then move up to a little more complex boat to continue
learning. Your in for a great adventure. Enjoy the ride.