You may want to check out www.centurioncrew.com
they have tons of threads on this topic. I have the same boat, first suggestion would be to get the switchblade as it not only provides downforce, but shapes the wave (you will also find others who completely disagree with me) The next thing to consider is how many people you have on the boat. For us it is usually my wife, I and 4 little kids, so we don't have a ton of people ballast. Start by filling all your ballast tanks, with the exception of maybe the front tank. Then take your People ballast and have them all sit on the side you are surfing, you need to get the boat to list to that side. If you are not having great success this way and don't have a ton of people, you will need to pull the hard tanks and put in some larger bags. The Enzo sac is great and will take the place of both of your hard tanks. I would think if you have 8 good sized people you will be okay, but to make it GREAT you will need to either get the switchblade, or put in more weight.