Mail_Queue and Spam

Hello to all, I want to use Mail_Queue to deliver mails to about 1200 members of a registered society. How can I avoid that the mails are qualified as spam? I read a lot about how the mail itself shall be constructed (real names for recipient and sender, reply-adress, no HTML etc.). But on two points I'm not quite sure: What about the mail's date? - If I don't set the date, Spamassassin will set a MISSING_DATE marker - If I set the date the moment I construct the mail for the queue, it can be more than 3 hours old the moment it is sent. So Spamassassin will set a DATE_IN_PAST_03_06 marker or corresponding markers if the mail is more than 6 or 12 or more hour old So what is better? Not setting the date at all or setting a date which can be too old? Or is there a possibility the avoid this problem? Number of mails to be send with 1 Queue (max-mails)? RFC 2821 says that delivery SMTP servers should not send mails to more than 100 recipients. That means that 1 mail shall not have more than 100 recipient. I will set only 1 recipient per mail. Mail_queue sends the mails one by one! (?) I vaguely remenber to have read that an SMTP sever should also reject the sending of more than 100 mails with similar content, if if they are delivered to the SMTP host one by one. I can't find the source of that information again (was it RFC 2821?). So, what is the best value for max-mails? My customer wants to send the mails by hand, so the packages shall not be too small. Thanks for your answers. And if you have other good sources of information on these themes, I will be really enjoyed. Best regards Sabine