Actually, the use of the eggs is not limited to the one-at-a-time application. If you are in search of dolls mainly, you may put an upper fragment + a lower fragment + a full egg to yield 2 dolls, guaranteed. Otherwise, the egg has its normal various potentials. But otherwise, one at a time is the way to go. There is a set of html files under the support folder in your D2 directory that I think you'll find quite helpful and informative. They include runewords, cube recipes, unique and set item lists, just to name a few. Check it out when you have a few moments. Beats having to chase down all that information on your own.