"High" speed is a relative term, but what is low or normal speed for other type of motors, for stepper motors would be high speed, so i guess you do need that. Because you do want your motors to still have torque at speed. Otherwise you run into problems with speed and accelerations.
You can use any angle, you only need to configure in firmware accordingly. Best types to choose would be those that have 1-2-3-4-(5max) ohms coil resistance and (min1-1.2A)-1.5-2.0-2.5A current. Especially if you plan to use 12v power supply.
You can use any angle, you only need to configure in firmware accordingly. Best types to choose would be those that have 1-2-3-4-(5max) ohms coil resistance and (min1-1.2A)-1.5-2.0-2.5A current. Especially if you plan to use 12v power supply.