Re. method #1: The pulse repeat rate for standard hobby servos is 50 Hz. That is, for a 1.5 mS centering pulse, the blank space is 18.5 mS. I read about the technique of lengthening that space (i.e., decreasing the pulse repeat rate) to slow down a servo about two years ago. I have not experimented with it, but it came from a university source. I have no idea what range of speed control you can attain with it, but the experiment with an MCU or 555-produced servo signal should be quite easy to do. I suspect the range of control is quite limited and don't really understand why it works.
John