Use the same username and team number on as many computers as you like, even if they are networked together.
The only conflict that can arise is if you run more than 1 F@H client on a single computer (e.g., CPU and GPU clients, or multiple CPU clients on a multi-core or multi-CPU computer). In that case, each client has to be loaded in a separate directory, and a unique Computer ID (from 1 to 8) assigned to each one on the initial configuration.
The type of Work Unit downloaded depends on the client you run and on the physical CPU type. All that is done automatically, without any configuration needed. While the same Project number may be run on several computers, each Work Unit will be a different Run/Clone/Generation. Each combination is run only once, unless it is not completed successfully within the deadline.
i7-3770S (SMP), Q9650 (SMP), T9400 laptop (1xCPU), and 2 old Dells Folding@home and elsewhere.