For specifically setting up a DD Wakesetter, check out this link:
http://www.themalibucrew.com/forums/index.php?showtopic=1841&hl=ballast Generally speaking, a larger board will let you get away with a smaller wake. We use the 5'6" Broadcast, but I'm actually looking at getting an Inland Surfer (either Blue or Green, haven't decided yet) for my husband. He's a big guy & has more difficulty with the Broadcast, but on the Inland he can ride it all day long ropeless.