I’ve opted for the auto delete of old spam messages through Mail.app, using the method explained in #5.3 of the manual. It’s working beautifully, bar one oddity. I’ve no idea whether this is a SpamSieve issue, a Mail.app issue or a Gmail issue - so this post may or may not belong in this forum. But anyway …
I have three accounts, and therefore three “SpamSieve - …” rules at the top. (Also a “remote training” rule at the very top - per manual #5.4) The 2nd of the three is for a Gmail account, which I use as secondary account almost entirely for spam reporting and other ‘unsavoury’ functions . Every incoming message in that account is spam, so I have no need to confirm the status. Therefore I want every item in that account marked as ‘read’. What I’m finding is that the read status is inconsistent - some messages appear as ‘read’, others as ‘unread’.
Any clues? Suggestions?