Turns out the description on the back of the ink bottle is actually what it shows.
Instead of putting a big wad of silk fluff into the basin in the body, you are supposed to stuff the fluff equally between the two bags in the box and place that in the basin. Like this:
except every picture I see of a sumitsubo has a big ball of silk fluff and that is what came out of this one. I think I will stick this design below.
Now I just need some silk string.