Choosing observer points for Viewshed tool in ArcMap to identify visibility of landform

I am using ArcMap 10.8.

I want to create a polygon that shows all the areas within a region from which an observer could see a specific mountain.

I created a polygon around the mountain, and I’m going to create random points within the polygon to use for the observer points in the viewshed tool. The polygon is about 690 square kilometers, and I want to minimize the number of points I use for the viewshed so it doesn’t crash my computer.

Is there a way to estimate how many observer points I should use based on the size of the landform polygon to get an accurate representation of visibility of the whole mountain?

Edit: I have to do this for a few features, including a single peak (one point on top should work), a basalt spire with a flat top (one point on top is insufficient), a ridgeline, and a small mountain range. For the ridgeline and small mountain range, maybe a point on each peak or high point would be enough?