Your explanation is wonderfully clear, Sharon! I'm sure that will be helpful for anyone having slow-loading forum issues, too, though I like to keep my site preferences at 500 so that I can utilize the database more efficiently (and the thumbnails there keep it fast and clean).
But I don't mean to assume that is what other's mean when they say their preference would be for shorter blooming threads. I can imagine there are different approaches for different folks, and seeing that you and others refresh the forums with new threads after they've gone long has always been admired.