Making a Gelatin Printing Plate

I just poured my first Gelli plate for printmaking. The directions should have been simple, but there is a discrepancy between how many packets of gelatin to add to the mix. It says '7 1 oz packets' but the whole box weighs 1 oz and has 4 packets. So as per the directions I have to let it set overnight. I wanted it to be twice as thick so I will double the recipe next time. I don't have enough glycerin right now to do another batch. I made my best guess and we'll see how it turns out. Also, the new clear acrylic frame I'm using as a mold wasn't really flat on top when I opened it. It was slightly convex. So I hope it all comes out. I think that is why I've been procrastinating. The instructions are a bit ambiguous.