Is it though? Should I post my gn note at 9pm US-Eastern time, so as to be early enough for all but the earliest to bed of the north americans to see it?

I am usually just signing off from work and getting dinner sorted at that time, and will probably be up for another 5-6 hours.

Nope, I'm fine posting a gn note whenever I get around to it (normally around midnight to 1a US-Eastern time.), but do not intend it to mean I am going to sleep and will no longer be reading or posting notes. I just mean to communicate to the wider nostr community, many of whom may be waking up in Europe or getting on with their day in Australia, that I am beginning to wind down my day and may or may not respond to communication for some hours. I say this respectfully and lovingly. I also try to leave my #nostr family with some thoughts or updates to take with them until I return.

Cheers, fam!