You can get better points per day with the SMP client and you only need to run one instance.
To run two regular clients:
You can only run one GUI and one console or two consoles.
You have to configure a console to a different MachineID.
To reconfigure: make a shortcut to the console exe
Right click the new shortcut and select Properties
In the Target textbox, at the end of what is in there, add a space, a dash, and "configonly" without the quotes. Also add the local switch.
Here is how it should look:
C:\Fah\FAH5.04b.exe -local -configonly
If your path has a space in it the first part will be in quotes.
When you run this shortcut the client will reenter configuration. When you get to the question about Advanced Options answer Yes and you will get to where you can change the MachineID.