1) you can configure the amount of simultaneous scans, so you can always tweak it to work. You can scale up from running on a laptop to running on 3 separate machines (service,database,webserver)
2) Yes, you can choose to create a new virtual directory
3) There are different parameters for this (explained in the documentation)
You can scan triggered by lsclient, you can adjust the waittimes for each item to scan, and you have active scanning (premium), triggered by lstrigger (premium)