I added the 750LB rear sacs and it made a huge difference in my Supra. I fill the rear corner 750, wake plate 3/4 up, at about 10.6 and I can surf all day.
Obviously, you can go to more extreme measures with more weight, but this is the most simple way to upgrade and get you a sweet spot in the wave. The sac size is 50 x 20 x 20. Fits real nice in my rear compartments of my '08 Sunsport 22V. You can pick up the sacs at
www.wakemakers.com, you will need the male 3/4" quick disconnects to plug into your existing connectors.