Surfing behind a ski boat

Hello everyone. So i am surfing behind a 2000 Malibu Sportster. I am having trouble finding the sweet spot. I am using the wedge. I keep getting a huge rooster tail. When I don't get a rooster tail, I can not find the sweet spot. Can anyone help me how much weight I need and where on the boat that weight should be? And I am not alloed to have ballast on my lake. The lake is too small and our docks are to low to the water for the big waves. The only weight i can have is people. Please Help!!
Thanks!