They'll fly up while they have just enough light to see, a few minutes before dark. I'd wait til it's really darkto set up my blind or before the moon comes up. Then I'd get to the blind long before it starts getting light.
Plan B: Either stay put and wait. A decoy or two might get a tom interested eventually. Just don't call much when they're in the field. Or, When they leave the field, abandon your blind and use the natural cover to set up on them someplace else.