For anyone wanting to feed egg yolk to fry, this link is one of the best explained I have come across.
http://www.fightingfish.com.au/article.php?id=5

I have to agree 100%.
The only thing is that he uses too much water for my taste, lol.
Eggs are cheap. Unless you are having a lot of spawns you shouldn't need to have to freeze eggs cubes.
Also, I know that many people start feeding it as soon as they are free swimming. I have always started all of my fry on bbs from day one that they began free swimming, and never had an issue with it.
But it is a good back up to know incase I have a MW crash (my back up) or my VEs (the other back up) spill all over the place, lol.