Your stratum and dynamic difficulty appear to be working very nicely. Well done. The nice thing about your vardiff is that once it has found the right difficulty it does not fluctuate. This is important with stratum because of the potential for lost work +/- rejects across difficulty changes, which I see alot of with EMC for example. You also seem to have made good inroads into the speed of block change detection closing the gap on slush markedly.