a continues line from the forward bulkhead fixed at the bottom along the bottom of the lee cloth through grommets (or a sleeve) to the aft bulkhead through a small eye and up to a small block hooked to the pad eye at the top of the lee cloth. From there along the top through some small shackles (so the line will slide more easily) to the block and tackle. The other end of the tackle would be fixed to the pad eye back on the forward bulkhead at the top of the cloth. That way when you tension the block and tackle, the top and bottom would be tightened at the same time to what ever tension you like. Both ends at the top, one of which would have the small block, would have some snaps so you could lay the cloth down under the cushion. In fact, all four corners could have snaps so you could remove the lee cloth all together. You would end up with two pad eyes at the top of the cloth and two small eyes at the bottom ends. This way you would eliminate the need to figure out how to get the bottom line tight enough.