Giving you what you want
Here it is, I'll give you what you're asking for, not the standard advice, but my thoughts on the topic that come from 20 years of playing poker, and about 10 of them taking it pretty seriously. 20 buy ins is inadequate. Pros who preach this still go broke. You're no pro. Therefore what is inadequate for the pro is woefully inadequate for you, and me. 20 is solid insuance, don't get me wrong, but really it only serves to insure against math boning you. If math were all that got in our way then every physicist would be a pro.
You sound as though you'll have your moments, like we all do, where you do a fair share of sticking it to yourself without math even needing to help you out. Before you can say anything about your game you need a sample size you haven't even thought of getting at a limit, typically between 50,000 and 100,000. It is very possible, likely even, that you'll manage to get yourself rolled to move up to 5nl by playing 2nl with your 50 stack, but it is also very possible, though assuming you play well not so likely, that you go bust.
But beyond trying to crush your dreams. What you've read means nothing till you have practiced it. Get hands in. Tons of hands. Definitly learn to play more tables, no point in moving up in the micros till you can handle 6 tables at once. The money is softer, so more tables of bigger fishies equals more money. I have more to learn than I've even begun to know about this game to play is perfectly and I'm a consistent winner over quite a long term. You have to stay humble, and be willing to take good advice, and not push for your own justifications.
Perhaps check out some of Alan Schoonmaker's books. They are about you and your psychology, not the technical play, and it seems you would benefit from some of this approach if you want to take it seriously.