I'd say 150K is enough, as long as you don't withdraw any of it. I semi-retired 3 years ago when I passed 100K net, and started only working part-time (2-3 hours/day) to cover living expenses. I'm 38 now, and although my goal is full ERE, Partial ERE is obviously great, too. So as long as you have a basic capital egg of +100K, don't withdraw it, grow it, and can cover your living expenses (which, given your apparent talents, shouldn't be a problem), you'll be good to go.
Along the way, I strongly recommend you learn how to invest and make your 100K-150K grow. The initial investment of time & energy might be undesirable (since you clearly know what your passions are), but down the road you reap more benefits. I'd say it takes an initial 100-300 hours of basic self-education (all you need is on the internet, but you have to sift through quite a bit of junk & BS) to become a semi-competent investor.
Unlike most other ERE investors, I would recommend capital growth instead of dividend/income growth. You're young, so you have time to build your capital instead of rely on it for income. And since you're good at chess, your learning curve with investing will likely be shorter - the stock market is just one big chess game: analyzing problems/situations, learning your opponent's patterns, projecting potential outcomes, readjusting to unexpected situations, all of that is necessary for investing.
I'm no genius, but I've doubled my investment capital (individual stocks only) in the last 3-4 years. That's not really likely with dividend stocks. I'm not against dividend growth stocks - I plan on switching a large % to them myself after I've hit my capital target. But when you're young, your aim should be growth. Don't ever let anyone tell you that it's impossible or risky. I'm actually quite a risk adverse person - never yet gambled in a casino before in my life.
Simple observation of the stock market (and basic math) will show you that when a $20 stock goes up to $22, that's a 10% gain, which may take only days or weeks. Do that with all 5-8 stocks in your portfolio, and your account is up 10%. Hold some stocks longer-term, they may go up even more. So all you have to do is find stocks that have a very high probability of going from $20 to $22 (in the case of a $20 stock, I prefer upside to $30-$40). This is a simplification, but you probably get the idea.