Hi there.
I am one of the primary troublemakers who keeps giving Bo more stuff to do on cFIREsim... As he indicated in an earlier post, I am quite interested by withdrawal methods. It totally mystifies me that some people are extremely methodical with investments and optimizing spend and tracking budget, but yet just wing it when it comes to planning for retirement withdrawals... So I played with various methods & metrics with my Excel sheet, and have been torturing Bo ever since to improve his wonderful tool to support more and more features... ;-)
After exploring Guyton-Klinger, then VPW (to which I contributed a bit), then creating this RA&A simple approach (which has some drawbacks - just to be clear), playing a bit with some other ideas, I made a big loop, and finally realized that once you factor in the OTHER sources of income (SS/Pension kicking, inheritances, some side/part-time job post-retirement), then a variable method like a simplified form of G-K combined with a spending floor and cap is my preferred method... Buy hey, I'm still learning, so we'll see where this journey will bring me... Notably when I start doing it for real with my early retirement to come (soon!)... ;-)
In any case, kudos to Bo for the best online retirement calculator I've seen so far, and for being so accommodating with feature requests.