I WOULD HAVE THE HOLE WIELDED UP.BECAUSE THE FLATTER AND TIGHTER YOU CAN GET YOUR POLYMER THE BETTER THE BOAT WILL HANDLE.I LIKE TO LET THE SUN BAKE ON IT TO LET IT STRETCH AND THEN PUT THE SHEET ON 4X4 PATTERN. AND THE REASON FOR THIS IS WHEN IT GETS COLD IT CAN'T GO ANYWHERE,ON WHEN IT IS HOT IT CAN'T GO ANYWHERE. IF YOU TAKE A COLD SHEET AND OUT IT ON ,WHEN IT GETS HOT IT WILL GROW.AND THAT'S WHEN IT WILL RIPPLE IN BETWEEN THE RIVETS OR SCREWS.IF IT IS HOT AND STRETCHED IT CAN'T GO ANYWHERE HOT OR COLD.