Divide both the water and oil doughs into three equal pieces (6 pieces total) with a bench scraper (for accuracy, weigh with a digital scale, if you have one). On a lightly floured surface, roll each portion of the oil dough into a smooth ball. Roll out the water dough into 4-inch rounds. Working with one pair at a time, center a ball of oil dough ball on a water-dough round and pinch the edges together to cover completely. Place the ball seam-side down and flatten with your palm. Continue to dust with flour if sticking. Roll out the dough into a long oval, about 8 inches long, and roll up into a coil, starting with a short edge. Flatten the dough with your palm again and roll out into an 8-inch long oval. Roll the dough up into a coil, starting with the short edge. Cut the dough in half crosswise with a sharp knife. Place the pieces of dough cut-side up, and flatten with your palm. Roll out a piece into a 4-inch round and place the filling in the center. Pinch the edges of the dough together to fully seal. Place the mooncake on the prepared baking sheet and repeat with remaining dough and filling, spacing each at least 2 inches apart.