Arms 1-3 are elemental init. They put the element (or salt) on the duplicator and pass an atom to arm 4 if it was an element, then never do anything again.
Arms 4-6 are the elemental loop. It's 5P since that's the optimal amount (4->5 saved 0.52 sum) and also the most I could fit in the 24 period anyway.

The metal side puts an amount of quicksilver into arm 8 based on the input metal type (using arm 7 to pass exactly 6qs), which determines how quickly the lead can get bonded to it and move to the projector. Arms 12-14 just bring the metal to the output (or dispose of it).

It'd be nice if I didn't need to put so much effort into merging the two streams, but I can't think of a good way to make the outputs be close enough to do it more cheaply. I'm not happy with needing to place the disposal, but it was simpler than finding a way to transport the gold through my mess to filter it with another hexarm loop that would probably be more expensive anyway.