I couldn't seem to find anyone that did this already. The key things are being silent AND hopper speed AND doesn't leave any items in the droppers. A torch tower can be silent and not leave items behind, but it is 50% less capacity because the torches would burn out if pulsed at hopper speed. This uses observers instead of a torch tower which can transmit the hopper-speed signal perfectly.
Made a video as well. It's my first video.