You can add a simple resistor and change the delay time. If you want to hand solder one resistor.
Post #20 is very close to what is on the board. The schematic in post #1 is not what is on the board. What is on the board is in post #12.
What KeepItSimple posted will have the same problem. The opto, used like this will have a 2:1 variation in delay alone, if all other parts are perfect.