A console crane is as much a structural decision as a lifting one, and it is worth taking in that order.
The arm carries the load at a distance, so it puts a vertical load and a bending moment into the runway. The runway passes both into the columns it is fixed to, at whatever point the crane happens to be standing. That means the case your structural engineer has to check is not one fixed load but a moving one, and it changes with reach.
We calculate the loads and moments for your configuration and issue them with the quotation, so the runway and the fixings can be verified before anything is ordered. Where a building was designed with this in mind the check is quick; where it was not, it is far better to find that out now.
We do this as a retrofit into an existing building where the structure allows it, and the verification comes first in either case.