7 arms, running up again a waste arm that had to manage two things at once.
6 arms by collating two to the duty of one.
5 arms by collating another two to one. Geometrically it shouldn't work, but by using two glyphs, more things are possible.
So I think I'm done improving this one.
No solves past this point can have 5 arms, unless they pack in better, as this is not only perfect throughput but the fastest possible solve. And I'm at least halfway confident this is the minimum arms for perfect throughput.