R 10/3
I 90
G 775

Three pipelines:
1) takes 2 gold, makes one product and one tin
2) takes 2 gold, makes one product and two quicksilver
3) takes 1 gold and the waste from the other pipelines to make one product

Unfortunate timing makes pipeline 2 need to ditch the first quicksilver and take the second from the next pair of golds.