Both are equally easy to construct. The difference is that one is only going to flow a pre-set amount of water (maybe too little, maybe too much) depending on the dimensions of the opening once the reservoir level is set unless that opening is adjustable. The other has flow regulated by a valve, which you will have to use anyway, so volume of flow, depth across the table, is adjustable without experimenting with different sized openings. No matter what design you choose, make sure that you tightly classify the feed so that gold is king.
Good luck.
PS In either instance, introduce the water into the reservoir evenly across and under the water fill level to prevent bulging and/or bubbles.