I weighed them to see if there was an average % of egg mass that became a hatchling.

You could also weight them to see if your females are producing more eggs as they get larger or if they are producing the same number of eggs that get larger. (this is called "The fractional egg hypothesis". This hypothesis is pretty cool and there is a research paper by Neil B. Ford and Richard A. Seigel from 2010 in Herpetologica that explains it.