The piston is actually him. Certified BANGER of a solution, it may get beaten by a cheaper but slower solution. My previous solution made one metal every 6 tape-loops and was like 1300 sum. This one beats that mark by a mile by being way faster on the metal side while maintaining cost.

Solution explanation, (It is long):

Saltlikes:
I did not use quintessence as it is expensive and hard to operate. I store the cardinal type by duping every salt input. The input suppression prevents the second template atom from ever spawning, saving some G in the process. I check if the input is saltlike by calcifying the template atom and triggering animismus. If it is then I start outputting the duped salts using anime output as a wand. The rest of the machine won't work as it needs an atom to keep going. I expect a lot of people to find this exact setup or similar approaches as it gives 3 or 4 rate on each saltlike for little cost.

Non-gold metals:
Every 3 cycles I pull one metal + one quicksilver, for a total of 6 each per tapeloop. When the rank of the metal matches the template atom it purifies and its product is used as a wand to retrieve the remaining 5 metals. One of those metals is used to replace the lost template atom, resulting in 4 outputted metals every N tape-loops, where N is 1 + the number of qs required to reach the rank of the template atom. The output arm is reused from the saltlike pipeline saving G. The product of the purification is disposed of, so the area is finite. The main advantage of this setup is that there is almost no wasted quicksilver and the lesser metals get outputted at reduced rates because once the metals match the template they automatically get outputted. The average rate of non-gold metals is Tapeloop * ((1+2+3+4+5)/4)/5 which is pretty low. Tapeloop is 18 for this solution.

Gold (painful):
Gold cannot purify so the wand trick does not work. This was the hardest part of the solution by a long shot. Once enough loops have passed we want to use the template gold as a wand because we know that all the metals have become gold. However, this means grabbing the template from the purification glyph, which results in a wrong grab for the case of the other metals. However, for every 60 tapeloops (LCM of 1,2,3,4 and 5) we can guarantee that, for a brief moment, the only atom that would be there is the initial template atom. By delaying the goated piston by roughly 1080 cycles, we can grab the gold template atom from the purification glyph and feed it to the arm that builds the output ball. Additionally, since no gold purifies, the output ball can have 5 gold, which makes the rate of the gold case lower than the silver case; (6/5 < 5/4). This only solves the first output case. To keep outputting gold, we cannot grab from purification ever again as we would grab other metal in the other cases. I used a grab conditional that only allows grabbing there the first time the piston starts running. After that, the piston grabs the wand from the left of the purifier. The arm that recycles the outputted metals conditionally places non-gold to be used like template atoms (reusing the same arm that places the first template atom), and leaves the gold in a spot where it can be grabbed by the piston. The piston rotates only once per tape loop, causing it to repeat every 6 loops, just enough time for the metals to become gold again. Since the piston rotates, the new grab will also happen above the purifier, that's why every tape-loop the atom from the purifier is briefly removed and placed again.

It took me way less than I expected to come up with this solution, even though it was my first solo computation puzzle. I don't know what to expect. This looks pretty clean and has pretty deranged tech. As a fun fact, salt also works as a template atom for this solution.