Start by drawing up the design in profile, then model it as a full circle — that should make things easier, possibly even obvious.
If you have difficulties, upload the profile drawing and your effort and we can walk through this with you.
It is possible to create a height/depth map and directly map light/dark to the Z-axis dimensions — a simplistic approach to this is shown at:
or:
or, one can work more directly, just drawing geometry which then cuts away:
there is at least one where a number of different tools are shown to realize a specific profile — post a drawing of the profile w/ measurements and we will work through that with you if you get stuck.