Process Color Printing On A One-color Press

On a multi-color press, the sheets in the delivery are complete and it is very easy to visually evaluate the color and take corrective action. Can you think of any way of simulating what the final color might look like between press passes? If you purchase or make any type of a multiple-sheet overlay proof, you can lay each independent color layer over the inked press sheets to predict what the color should look like when done. It works amazingly well.