Hi minion thanks for your posts,
A - "...Would be good to have a "Configuration > Queue > ..." start time / end time work setting linked to the Joomla Global date time..." = I simply mean that if I set 8 o'clock, it means 8 o'clock of my Joomla Global date time...
B - You wrote: "...I'm from Prag and I want to send newsletter for subscriber from whole world..." = I'm agree and this is why I proposed:
"...PS - An optional next level would be to bind those values to the multilingual where, for each language we can indicate a "Language UTC date time" / an adjustment of the time so that the sending times will be more appropriate according to the user's language..." OR, better, by following the Joomla User Time Zone field.
So if I set 8 o'clock and my Global date time is GMT-5, for the User with his Time one as GMT-0 his 8 o'clock will be 13 o'clock (1 PM for AcyMailing for that user...