Hi My name is Zach, I own two companies and I know exactly where you are coming from.
See, around a year ago, I was just a college graduate with a bachelors and no direction, I was given advise to work for a firm, though due to my erratic sleep patterns (not waking up before 9 and going to bed at 5am)
I was 100% not motivated to work for anyone else. I've been a great self started since I was a teenager, I've also had the luxury to learn the basics, and a few advanced things during my childhood, which now are a solid foundation for what I now do.
Fear, is a very rational thing, and I am very impressed with your plan to manage income risk; some (most) people just jump the gun, quit their job, risk and lose everything in the first few months. So if I could give one (first) piece of advise, may I say; relax, it's going to be fun, and if you don't make it, you will never ever say, "what would have happened if I had just tried".
Honestly, that's what motivated me. I kind of just woke up one day and asked myself, "I can make excuses now, but what if ten years down the road, and ask, what could have happened if I had just tried,"? Today, i know the answer, I'd probablly have a few less grey hairs, (I'm 20 right now btw) I'd probablly have a few more restful nights (there is (at least for me) a stress factor)
But, I'd also never know.
Today like I had mentioned I own two companies, one pays my rent, and the other is a startup that I've started. lol
So, in point, relax, and know, you will know what will happen, the risk can be worth the reward if managed properly.
Sorry, I don't really know what else to say, except good luck! Also please keep us updated, or if there is anyway I could help, let me know!