If all this sounds too complicated to intellectualize, the simple takeaway is the following:
A) Keep moving in the direction of niching down;
B) Don’t see niching down as a “night before niche/night after niche” deliverable. It is a process of constant finetuning. Balance the stakes by making a critical reasons-based mix of 2-3 areas;
C) Have someone with a healthy distance from the practice look at your niche development in context of deep knowledge of you.