This solve peaked when I dropped the lead in the purifier.

Here's the math: 4 out of every 60 inputs are buffered (that's when arm 13 goes all the way to the left). As for everything else, I'm not really sure. It sort of just happened. There's no waste and I never project lead so I'm gonna assume it's min rate

Rate: 120/7 = 17.1428571429