if a leaf will fall off by touching it, go ahead, otherwise let it continue to drain them.
if the white pistils are mostly new growth, might be near harvest window.. otherwise, may want to let them ripen up a bit more.
trchomes on calyxes
density of colas
pistil coloration and retraction (ripening makes'em look shorter, but eventualyl they curl up too)
use all three observable characteristics to determine your harvest point... it'll help keep you consistent when one is a bit odd and just in general.