Nabih observes the list. With no pressure or deadline it's quite easy to puzzle out.
The listings seem to indicate which walls of the canyon they are on, the "floor", upward from the river, and, it can be guessed, how far upstream or downstream they are from an unspecified center point.
The house of commerce is notably perched on the top of the Western cliff, shadowing the governor's manor on the east. Whilst the latter is far more prominent when moving into the city, the house of commerce could only just be seen cresting the hill: the eastern cliff-face being more jagged and sturdy than the more gentle slope of the western.
The current inn Nahih is residing in would be West-1st-FW9: as it is directly on the water and the closest building to that floor's section of millworks. Therefore any western-face houses are viable.
As Nabih finishes the final dregs of his coffee, a sound of clattering from below intensifies, and the wafting scent of breakfast preparations trickles in.
The guardsmen give a few puzzled looks amongst themselves, before cap speaks up again.
"There's a place we go for breakfast straight up the ladder out the left of the door, if you're hungry."
He stands as if to let Larok out, but sees the ruptured bolts and settles for unceremoniously kicking it open a little wider.
"Just remember, if you go after that punk, we will be forced to come after you, and when we all fail, the council will put a bounty on your head."
"Honor is nice. But don't be an idiot."