Yes, you would be able to put a couple of small marks (one at X 17, Y 0 and the other at X17, Y15) with a small V-bit before you release the clamps. Then you could reference these marks in the next setup with X back in the zero position.
Another method would be carefully measuring the placement of the workpiece for each setup. This can be aided with jigs or material stops.
The maximum width that will fit in between the sides is roughly 17.5 inches. The front and back are open for shifting the work as much as needed
The maximum width the router can cut is 16 inches, but it can cut unlimited lengths using multiple setups.