I have cleared up my earlier confusion between the meaning of "Share Ratio Limit" and "Stop seeding when share ratio reaches", and have read the FAQ:
Seeding torrents have no queue position! Why? ¶
Seeds use something called "seed rank" to determine which should be active and which should be queued. The seed rank is determined by the number of seed cycles a torrent has completed. Torrents with fewer completed seed cycles are prioritized for seeding. A seed cycle is completed when a torrent meets either the share ratio limit (uploaded bytes / downloaded bytes), the share time ratio (time seeding / time downloading) or seed time limit (time seeded).
If I read that right, though, my settings:
Share Ratio Limit: 1.40
Seed Time Ratio: -1.00
Seed Time (m): -1
Stop Seeding when share ratio reaches: 1.40
Should result in 0 seed cycles for all torrents, and thus an equal priority - the Time settings are unlimited, so they can't ever cause a cycle to complete, and if a torrent reaches a ratio of 1.40, it should stop seeding.
However, I have a wide variety of seed ranks in my seeding torrents. Can anyone explain that?
A further puzzle lies in two particular examples - two torrents each with x(13) peers - but the one with a seed rank of 37 was actively seeding, and the one with a seed rank of 0 was cued. I would have expected the reverse; perhaps seed rank is inversely, rather than directy, proportional to seed cycles completed?
Any information appreciated.