How to know Hall Effect Sensor Spacing in BLDC

When using hall effect sensors in your Electronic Speed Control design, how do you know the optimal number of Hall effect sensors and how best to place them?. I know that 3 are typically used but I can't seem to find any resources on why exactly 3 is the optimal number to use.

PS. I am designing a 6 pole BLDC motor.

Thanks in advance.

Hiii mikeking14

PS. I am designing a 6 pole BLDC motor.

Are you designing the BLDC motor, or a driver circuit?

( in this video BLDC motor design is their.

In theory I read, their are two types of placements for the hall sensor which are 120 deg interval and 60 deg interval placements. The outer periphery of the motor is divided into segments, which is the number of pole pairs. Each segment will contribute 360 electrical degrees. first calculate the calculate the perimeter and place the sensors.

If my analysis is wrong please inform me