Subject: Re: help finding a Mungo post
Take a look at post 8287 here on the BRK board. It might be what you are looking for.

Yes that has some of the information I was looking for.

Also 2517:

So, the percentage of your portfolio you can liquidate and spend each quarter is proportional to how much this number has gone up.
To the extent that the valuation methodology is valid and the smoothing isn't too extreme, by construction your portfolio will always have the same real value and it will last forever.

<snip>

For a SWR strategy based on this, I think it's OK to put a floor on the withdrawn amount. But that's a matter of taste.
(my personal favourite version pays out only 90% of the allowed amount each quarter to give slight long term growth, but also has a floor payment of 1% per quarter)