You might want to make sure your one the same page when it come to sheet size.
I've seen different sizes.

I buy gelatin in bulk at the place where I buy my flour. I've had to research this before. According to my notes, 4 leaves equal one teaspoon of gelatin sold in bulk, which in turn is about 1/4 of one ounce. What exactly does your recipe call for? ;o)

Oh and by the way you can use a large bowl full of ice and a smaller bowl for the gelatinized liquid to cool quicker than the refridgerator. Just set the small bowl into the Ice of the larger bowl and stir.

First, know the total measurement of the liquid you want to set with gelatin. Then take a smaller measured amount of that liqiud and add your gelatin keeping track of the amount used. Each time you add gelatin cool your liqiud as a test to see if it sets if not add more. once the liquid sets. Then you have a ratio.

For example: If you have a gallon to set with gelatin pour off a qaurt to test. If it takes 2 sheets of gelatin to set the quart. Then it will take eight sheets for the gallon. Don't use this ratio I don't remeber what it is. But I have been here before and with out asking the chef who handed me the gelatin for instruction this is how I figured it out.