A Question re ATR

I wonder if anybody would be able to help with a couple of ATR queries?

I'm currently trading a 1-hour time frame, and was wondering if anyone has an opinion on the optimal ATR settings for this time frame?

Also, given the recent high volatility and commonplace one-off market shifting events, how reliable is ATR these days anyway?

Thanks in hope.

ATR is 100% reliable its just a statistical measure afterall.
I like to use ATR 24 or multiples of it on the hourly, for obvious reasons.
I think ATR settings should be fairly short or we defeat the object of applying the measure at all.