Hi Christian,
Perhaps you can give me a hint as to why inserts slow down. I was imagining that most of the indexing work would be in the Optimize afterwards. Sounds like it's also a lot slower relative to giving a single file that contains the same as many documents too, right? Somehow this doesn't rhyme in my mind, so I must be missing something.
I will try find the time to try out the latest snapshot, but from what I read I guess you're not expecting greater Add speeds, just faster Replace.
Gerald