he used 1k ohm, so try that.
but any value higher may work up to a Meg or so . . . . . if the resister starts to get warm try upping the value. . . .
But as you ask Deaky has tried&tested @ 1K ohm.....
I've just ordered to 2W 1K ohm myself to keep in stock.....
*****************************
The resistor just bleeds off any voltage/current leaks via the BCM or stray capacitance that can cause some or all of the leds to glow dimley.
a too lower resistor value will run warm/hot when the LEDS are running . . . . . if it stays cold/cool then your good.
******************************
Yep, I ordered 5 2W 1kOhm guess I can put a couple in series if I need