@dabears - I almost missed your question embedded in the quoted material. I would only use a non-IRS calculator for a rough estimate, the IRS materials are pretty clear and you should calculate your own number and method following their rules so that you can back it up. The percentage depends on your age (or joint life expectancy, if married), a calculated interest rate, and the calculated qualified plan's starting balance.
I'd start with the IRS FAQ's (
http://www.irs.gov/Retirement-Plans/Retirement-Plans-FAQs-regarding-Substantially-Equal-Periodic-Payments), if you want to get comfortable with going this route. It's quite a commitment for an ER, as you have to choose one of 3 methods. The one I personally prefer, that adjusts with portfolio (RMD method), the payment is recalculated each year. There are also two fixed (amortization/annuitization) methods which allow you access to higher payouts, but this fixes the dollar amount paid and could be problematic if your portfolio takes a substantial hit in the early years. You do get a one-time change down to RMD, but you've still technically overdrawn on a critical year.
The good news is, if your portfolio goes to zero, the IRS doesn't charge you the 10% penalty :)