i've made these crackers about a dozen times now. some lessons learned...
1) i now have an inventory of 8 different seeds, so i used a big tupperware-like container where i've basically mixed in a cup or more of each. when i make the recipe now, i just scoop out 1 1/3 cups of this mix. a lot easier.
2) i've settled on one hour at 300° F (convection bake setting) as the cooking time. i then cut/ score the still hot and moist sheet right out of the oven.
3) keeping the oven door open, in about 10 minutes it cools to where i put it on the "warming" setting at 140° F for 2 hours. about 1/2 way through, when they firm up a bit, i turn them over off the parchment which collects a bit of oil.
4) after 2 hours i turn off the oven and let the pan cool down still inside. in about 1/2 hour they will be cooled and crisp.
5) store in a tupperware=like sealable container.