Control servo 360 degrees!!

Hi,
I have seen on YouTube how to modify servo but the problem is that you can't control them like usual servo.I want to control a servo and write degrees so it's possible to modify a servo and then control it with milliseconds? And write 360 degrees

What I know about the modification on servos is that the engine limitation is removed, so you can send commands to move it into 360 degrees back or forward or even continuous rotation.

One problem is that the potentiometer loses its reference, once that its axis is removed too. If you find a way to measure the potentiometer's value to obtain how many degrees the motor is moving, then I think its possible.

One possibility is the use of an encoder to measure the angle variance.