I see that the feed water from the pipe onto the table is not consistent, and would like to plug some of the holes to get a better flow from the remaining holes. What would you suggest as the best material to seal some of these holes?
I would not plug any holes up. I modify my Tables so that water enters each end of the cons wash water spray bar. This seems to even out the water pressure/flow better. I add a discharge hole at each end to ensure that the water spray is reaching the extreme sides of the deck. Plugging holes will create other problems, like concentrating the flow to a smaller number of spots on the deck, thereby washing down on to the cons line too aggressively. You want to achieve a gentle, even flow of cons wash water. With some feeds, one can back off the cons water to a dribble. Any higher flow will try to wash some of the gold down slope. So it is a balancing act to get the table tilt, water flow and bump just right for your feed material. After a few goes, you will get the hang of it. (Yes, the wave table can also be termed a bump table because of this bumping!)
Always have the dummy sample available to test your set up.
Try not to dump lots of cons in to the catch trough. With small sample runs, it’s best to allow the gold-rich cons to just trickle over in to the catch trough. You should be able to watch the gold particles ride up slope and over-top in to the trough. I often fit a cork/plug in to the cons discharge hole. Any gold will then collect in the trough, which one can later wash in to a container. By plugging up the hole, the wash water fills the trough and evenly flows down slope from the weir.