Calculate your board volume based on your surfer profile then build your board.
This volume chart is a loose recommendation. It is not gospel. So many factors go into the calculation. Size; Age; Ability; How often you get to surf; Main goal; Cruise? Have fun? The most important thing is that you trust your shaper. I have 50 years and over 100,000 boards designed and shaped. I am looking out for your best interests.
Want more insight about what size you should get? Read "What Size Board Should I Get" written by Rusty himself.