A 100 ohm current-limiting resistor for the Chinese LEDs does not allow 60mA:
1) If the LEDs are typical at 3.4V each then their total is 13.6V for four in series.
2) The saturation voltage loss of a darlington transistor is typically 0.75V.
3) Then the 100 ohm resistor has a voltage across it of (18V - 13.6V - 0.75V)= 3.65V.
4) Then the current is 3.65V/100 ohms= 36.5ma.
If the LEDs are 3.0V then their current is 52.5mA.
If the LEDs are 3.8V then their current is 20.5mA.
Measure each LED, sort them then calculate the resistor for each string.
Like I said, a 555 will never time-out if its trigger pin is held low. It says so in the datasheet and that is why the input capacitor that I recommended is used in the 555 article you found. The article does not have page numbers so I attached the schematic here. His capacitor is 10 times more than yours but I think yours is better because it responds quicker.