HN is read worldwide. There are obvious peaks and troughs. I would suggest that timing for US west coast breakfast/morning, or Western European breakfast Morning or Asia (Japan-Korea-HongKong-Singapore) breakfast morning wasn't bad, but would obviously favour a demographic who want to see fresh HN with their kibble.

I have never posted any story with regard to time of day. But I've also never felt I had a success flood.

I have been told to consider re-posting after a week or two if it doesn't garner reactions. Inside that timeframe you might be seen as a being a bit over-eager/spammy.