We worked this out to be (10(R - 16/7))^2.

Clarissa did some good work figuring out the metric for this one. I was a little disappointed there was only one metric involved but the actual solve was pretty interesting. I think we are pretty near min cost for one reagent but I'm not getting my hopes up. We theorised combining the two single arms into a hex arm but couldn't find a layout that fed into it. I'm 90% its geometrically impossible but they're could be a layout we missed. maybe there's just a cheaper way to do it in general....

That aside we didnt explore 2 reagent solutions much. It would require reusing debonders to get under 180 cost. It doesn't seem very possible but I look forwarding to see how rebix did it.