Somedays sluice

  holes in line mate that's the go. Also on the bottom of the mate i snip off that little rubber lip which is on the inside of the hole. cheers

Yes all in line ! Works ! All this trying to slow down the flow of sand over such a short distance is ,in my opinion , not warranted ! But where your metal riffle cuts across the mat you have to fill the holes with a good silastic
So that the water can't get under the riffle edge and blow out the cons !

Oh yes what whiskers said too !

Anyone got a hanky, need to wipe some egg off me face!
Thanks peoples and yeah I do do the trimmy thingy  

On the other hand   if it works it works, right