In what context? Hand-to-hand fighting for a police officer? A soldier? A private citizen protecting themselves from a criminal attack? A bar fight? Fighting in a MMA match or boxing ring?Ok...well I should have a decent chance at learning principles of hand to hand combat. It seems very simple to say so but really that's the idea. I want to develop a rudimentary understanding of the principles of hand to hand combat. I believe that I can do this without much instruction from a martial arts expert. And I believe that by developing this learning, without instruction, I'll also understand more deeply the process of skill acquisition.
It's not so simple a thing, huh?
You want to know what people have done for "solo training" in the past? Look at the kata or forms in various martial arts. One sort of form was developed as a way to study and practice the fighting principles of a martial system.
You say you're trying to learn about "skill acquisition." That's a broad field -- have you even looked into the psychology of learning? You can certainly develop some skill in movement, but in isolation, it's kind of like trying to learn to play a musical instrument as part of a band without actually playing with anyone else. Or learning to play football by running pass patterns or practicing blocking schemes all by yourself. There are nuances and elements that you simply aren't likely to find without the direct input of an experienced instructor. And, if you do, it'll be at the expense of pain and wasted time on trial and error.
Here's another analogy, for what it's worth. It's certainly possible to travel across the Atlantic by first improvising a float by grabbing a log, then deciding to hollow it out into some sort of dugout canoe, and so on until you've built yourself an oceangoing liner. Or by doing experiments with kites, then building a powered plane looking at the Wright brothers's work, then a larger plane, and again through the stages to an SST. Don't you have better things to do with your time, since you can book passage on an existing liner or airplane, and get there in a matter of hours or weeks? What do you hope or expect to gain by your experiment with solo skill development that you couldn't gain by working with an instructor?