When using a Galil control system to control external anologe servo drives. Would I only need to tune the motors within the Galil board itself?

When running an ac servo drive in torque mode, is the drive simply varying current to the motor and allowing the galil to perform all calculations?

You'll need to configure (and wire) the drives to use a -10, 0, +10v signal and then tune the Galil board servo settings. Some drives will run smoother when set to velocity mode, so you'll need to experiment some.