Another thing to maybe realize is people who really know their stuff, who have ideas they know will work and have thought through their idea thoroughly, won't likely be willing to do 51/49 split.
And now you get into the issue that someone might end up with 50% equity and stop working - so then any and all work the other person does benefits the other one. :)
This is why I'm not a big fan of offering large amounts of equity to people that you don't know and haven't worked with before - so you know their value, and how well you get along.