I guess I'm misinformed, then.
The urushi I've used took a week to dry between coats on my stones. I used it straight out of the bottle, and the thickness was like molasses. Dries hard like a thick acrylic jacket, though.
In fairness, I've been told by a knowledgeable source that cashew or modern lacquer serves the same purpose, and doesn't give the amber hue that urushi does.