I just sometimes look at the milestone shape and see a solution other than the one shown. And then I feel annoyed because I need to complete the steps for the suggested solution delete the factory and start again.
For example milestone 9. First I will make these 2 shapes {XrXrXrXr:WbWbWbWb} and {XbXbXbXb:WbWbWbWb:XgXgXgXg} and then I will just use swappers to combine these 2 shapes into the final one {XrXbXrXb:WbWbWbWb:–Xg–Xg}. I think that this solution is better for scalability, or am I missing something?
My conclusion is that you could skip these steps and just deliver the final shape for the milestone. Perhaps the number of the final shape you need to deliver could be multiplied if you decide to skip the previous steps.