evaporation

Hi all I would like to master batch my lye but am not sure how to calculate the final volume. If, for example, I bought a 2ltr (2kg) bottle of distilled water and dissolved 2kg of lye in it, it would clearly not all fit back into the 2ltr bottle the distilled water came in, what would the...

I have read that Hot and Cod processes use up different amounts of water during making, how can we account for this in SoapCalc? How would we know about the difference in evaporation rates, etc? Is there a general guide / rule of thumb that we can follow for hot and cold?

So am I just a little weird to chart out my weekly weighing of curing soaps onto an excel spread sheet? I like soaping... I like excel works for me, but I feel like a nerd. I must say though, that I've noticed that the rainy week we had recently did affect the rate of water evaporation...