It took some serious work to make even just this little optimization onto my 3-arm tarcles design, but at least it's capable of operating at the full rate of the hex-arm; the hex-arm input method hard-limits me to 120c+latency (as it can only give 1 product worth of silver-fire compounds every 10c), so all 5 additional c are piston-related latency. I don't think there's much room for further improvement here.