The lighter the wind the less rocker you need.
Everything from 1,5cm to 4cm will work. Even 0 cm will be ok.
Make the line continous.
There is a nice calculator online for rocker calculation if a CAD software is not available: http://www.handymath.com/cgi-bin/arc18.cgi?submit=Entry
enter 150cm board (Width of Arc) 3cm continous rocker (Height of Arc) and you get 9,39 meter radius. This is your rocker line.
If you want to make the rocker "progresive" in the future then decrease the radius smoothly in 0,5m steps towards the board tips.
Add more rocker to a wood strip core. It will decrease (20-50%) soon after you take the board off the mold.
Concave should be 8-15mm for a wide (>45cm width) light wind twintip.
You can do it without concave, but you loose better planing, upwind, the board will be very flexible, etc.
Concave depth should never exceed a half rocker depth.
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