See the problem with 2x (or any other speed) is that the human is still slow so making a bound with faster speed might be hard to control.
And 1 millisecond will be way too fast like it is a non stop explosion.
Just make it half the normal amount.
just in case you didn't know, 1 second = 1,000 milliseconds. This means 1 millisecond waits will make your bound impossible to beat.