~10% rejects with 4.3.5 on the S2 now ... very reasonable! Great job!

Can you check what kind of rejects these are? Job not found or something else?
Looks like they're all job not found. Anyone have any tips on reducing those? Scantime and expiry I'm guessing?
Scantime is useful only for getwork. Nothing you can do here, but to try WestHash (if you are located closer to US West). Job not found are stale shares - your miner is too late.