You can run them all and create as many spreadsheets as you want, but there is no 'deciding factor.' There are so many variables and uncertainties, the best you can do is test your plan against past history (FIRECALC does that well IMO), decide how you think the future will compare with the past and build in any additional safety factor that allows you to sleep at night (if needed), have a plan B, monitor your progress and remain flexible. If you pull the plug with rigid expectations on your spending, taxes, investment returns, inflation, Soc Sec and other income sources, life span(s) and all the other variables - I guarantee many will be wrong (could be worse, or better!).
The FIRECALC graphs illustrate the uncertainty well. A given plan could fail before 30 years, or end with a bequest many millions more than the retiree started with - those and anything in between were real possibilities that actually would have happened from 1873 thru ending in 2011. And those are results showing the variability of real returns only! There are many other variables.
If you're waiting for a calculator/spreadsheet with no 'ommisions' - it will never come, guaranteed.
That said, (like me and others) you may need to try several calculators/spreadsheets to fully appreciate there is no silver bullet. You're (understandably) going through convincing yourself now, hopefully you'll get there before you drive yourself batty...