We have a 1982 SN model 2001. We use side sacks, and load the boat with people too (once we had 10 on our boat). Works great, but I wish I had some weight under the bow, perhaps 200 pounds or so.
We tried a water filled back seat. The wake was huge, but too steep.
Earlier this summer we forgot the pump so we ran wtih empty sacks and just three people on the boat. Our son was still able to clear the wake with ease and do a back-roll, even without the wake enhancement.