It is somewhere in the guides listed in the OP, it is a feature of RNG Reporter. You click on "Time Finder," go to the "Shiny Egg" tab, then enter the information and hit "Generate." It comes up with seeds that have at most 80 taps to reach a shiny egg of your choice of gender, ability, and nature.
Highest 4th Gen OU CRE: 1582.46 (#22)
The latest version of PikaTimer is here
. (Version 2.03- 4/15/10)
Pikachu25's RNG Shack
My White FC: 2537 5798 1419