Puck.IR() definition clarification needed

I wish to send a slow pulse train via the onboard IR diode, say [500ms on, 500ms off] repeat three times.

Just Puck.IR([500,500,500,500,500])...

What is the range (width) in msec that each pulse may be? For instance min 0.5msec max 500msec

It's large and small enough that you shouldn't have to worry. The minimum is going to be around 1/20000 (because the pulses are 40kHz) and the max is possibly even hours.

Q2: Does the array have to specify an exact count 'n' (on, off) cycles? For instance 'n' must equal 20

No, but ideally it'd be an odd number because of 'on...off...on' - a 'off' on the end wouldn't make sense

Q3: Does the tutorial at '(a tutorial on this will be added soon)' exist?

I don't understand the question - do you have a link to where it says that? The reference page mentions http://www.espruino.com/Puck.js+Infrared - which works.

However for some reason it's not turning URLs in to links properly - I'll see if I can fix that.