Atolls necklace sketch

It's time again for a big step by step project!
I'm probably going to get myself in trouble with this necklace, as I can already see that it's not going to be easy to achieve the results I'm wishing for, but I had to give it a shot. ;-)

I don't usually draw a sketch for my necklaces, but this time I thought it might have been a good idea.
The colors of the water and sand around the atolls and around the islands are shading in an opposite way, so hopefully with the sketch I will not mess it up.

I just hope it's going to work out, 'cause I won't know untill it's all done and it sure wouldn't be fun to have to take everything apart! ;-)