I think you're making this more complicated (and less accurate) than it needs to be. A good rough estimate is that you need 25x your planned spending:
https://www.mrmoneymustache.com/2012/05/29/how-much-do-i-need-for-retirement/https://www.madfientist.com/safe-withdrawal-rate/If you're asking about how to access funds before you're 59 1/2, read these:
https://www.madfientist.com/how-to-access-retirement-funds-early/http://rootofgood.com/roth-ira-conversion-ladder-early-retirement/The reason I think your approach is less accurate is that there isn't any good way to figure out how much you need to get to 59 1/2. You said you're 29 so you have 30 years in front of you. You need about 25x your annual expenses to be extremely confident that your money will last that long. However, there is a very high likelihood that you'll end up with far, far more than you need (double or more your starting amount) rather than running out. That's part of the reason that 4% not only works for a 30 year time horizon but it also is pretty close to what you need for forever. There isn't all that much of a difference between 30 years and forever in terms of the amount you need to have saved. If you save enough to get you to 30 years from retirement *and* you have the full amount you need being added to that (your 401(k)) then you will basically have saved double and worked a lot longer than necessary to do so.
Just get to 25x your annual expenses in your 'stache and make sure 5 years of that money is accessible to get you to the bottom rung of the Roth ladder. Once you start to get close - say 15-20x annual expenses - you probably should start to run through scenarios at CFireSim or FIRECalc. Then you can add in things like pensions or social security, additional medical expenses late in life, long term care expenses, consulting or side-gig income, etc. to get a more customized estimate than just the straight 25x.